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THE  PHYSIOLOGY  OF  THE  NEW-BORN  INFANT 


CHARACTER  AND  AMOUNT  OF  THE 
KATABOLISM 


BY 

FRANCIS  G.  BENEDICT 

AND 

FRITZ  B.  TALBOT 


' 


* 


WASHINGTON,  D.  C.  V 

PUBLISHED  BY  THE  CARNEGIE  INSTITUTION  OF  WASHINGTON 
1915 


<? 


SiOLOGY 

IBRARY 

G 


CARNEGIE  INSTITUTION  OF  WASHINGTON 
PUBLICATION  No.  233 


PRESS  OF  GIBSON  BROTHERS,  INC. 
WASHINGTON,  D.  C. 


PREFACE. 


The  investigation  on  new-born  infants  reported  herewith  is  a  natural 
outcome  of  the  attempt  of  this  laboratory  during  the  last  four  years  to 
secure  adequate  information  regarding  the  normal  metabolism  of 
infants  preparatory  to  a  contemplated  study  of  pathological  conditions, 
for  until  normal  data  are  available  an  intelligent  interpretation  of  the 
data  from  pathological  cases  is  impossible. 

The  observations  have  been  made  by  Miss  Alice  Johnson,  whose 
skillful  technique  and  experience  in  studies  of  infant  metabolism  have 
contributed  greatly  to  the  research.  To  the  trustees  and  especially  to 
the  superintendent  of  the  Massachusetts  General  Hospital  we  wish  to 
express  our  thanks  for  the  facilities  offered  to  us  in  the  prosecution 
of  this  study.  Through  the  kindness  of  the  trustees  and  staff  of  the 
Boston  Lying-in  Hospital,  a  large  number  of  new-born  infants  were 
made  available  for  this  research.  The  majority  of  the  infants  used  in 
these  observations  came  from  this  institution.  Much  credit  is  also 
due  the  nurses  of  the  hospital  for  their  active  interest  and  cooperation, 
which  materially  assisted  in  the  successful  outcome  of  the  research. 

NUTRITION  LABORATORY  OF  THE 

CARNEGIE  INSTITUTION  OF  WASHINGTON, 

Boston,  Massachusetts,  July  31,  1915. 


353768 


CONTENTS. 

PAGE 

Introduction 7 

Embryonic  conditions 7 

Post-natal  conditions 8 

Loss  in  body-weight 9 

Earlier  researches  with  new-born  infants 12 

Observations  by  Hasselbalch 15 

Purpose  and  plan  of  the  research 38 

Apparatus  and  tests  for  accuracy 38 

Method  of  computation 39 

Care  of  the  new-born  infant 41 

Statistics  of  the  observations 43 

Discussion  of  results 80 

Character  of  the  katabolism 80 

Respiratory  quotient  during  the  first  24  hours  of  life •. .  80 

Respiratory  quotient  during  the  first  week  of  life 89 

Influence  of  body- weight  upon  the  respiratory  quotient 91 

General  conclusions  as  to  character  of  katabolism  of  new-born  infants ....  92 

Basal  katabolism 94 

Total  minimum  heat-production  per  24  hours 97 

Minimum  heat-output  per  kilogram  of  body-weight  per  24  hours 98 

Minimum  heat-output  per  square  meter  per  24  hours 99 

Influence  of  age  upon  the  katabolism 102 

Influence  of  age  upon  the  heat-production  in  the  first  day 103 

Influence  of  age  upon  the  heat-production  from  the  second  to  the 

seventh  day 105 

Influence  of  length  upon  the  basal  katabolism 106 

Influence  of  activity  upon  the  basal  katabolism Ill 

Pulse-rate 113 

Physiological  needs  vs.  supply 117 

The  conservation  of  energy 118 

Body  temperature 118 

Methods  for  reducing  the  energy  loss 121 

The  energy  intake 122 

Probable  24-hour  energy  requirement  of  a  new-born  infant  for  maintenance .  126 

ILLUSTRATIONS. 

FIG.    1.  Respiratory  quotients  of  infants  found  at  times  during  the  first  24  hours.  .  88 

2.  Respiratory  quotient  of  infants  in  first  24  hours  referred  to  total  body- 

weight  91 

3.  Respiratory  quotient  of  infants  in  first  24  hours  referred  to  body-weight 

per  unit  of  length  of  infant 91 

4.  Minimum  heat-production  of  new-born  infants  per  24  hours  referred  to  the 

body- weight 97 

5.  Minimum  heat-production  of  new-born  infants  per  kilogram  per  24  hours 

referred  to  the  body-weight 99 

6.  Minimum  heat-production  of  new-born  infants  per  square  meter  of  body- 

surface  per  24  hours  referred  to  the  body-weight 101 

7.  Minimum  heat-production  of  new-born  infants  per  24  hours  referred  to  age .  .  103 

8.  Minimum  heat-production  of  new-born  infants  per  kilogram  of  body-weight 

per  24  hours  referred  to  age 104 

9.  Minimum  heat-production  of  new-born  infants  per  square  meter  of  body- 

surface  per  24  hours  referred  to  age 105 

10.  Minimum  heat-production  of  new-born  infants  per  square  meter  per  24 
hours  computed  per  centimeter  of  length  for  infants  between  l\  and 

Gdaysold 107 

4 


THE  PHYSIOLOGY  OF  THE  NEW-BORN  INFANT 


CHARACTEK  AND  AMOUNT  OF  THE  KATABOLISM 


BY 
FRANCIS  G.  BENEDICT  AND  FRITZ  B.  TALBOT 


INTRODUCTION. 

In  our  observations  on  the  gaseous  metabolism  of  infants,  which  were 
begun  over  three  years  ago,  we  have  been  impressed  by  the  fact  that 
while  observations  on  three  or  four  infants  would  admit  of  conjectures 
which  might  subsequently  be  in  part  verified  by  multiplication  of  data, 
yet  of  themselves  they  could  necessarily  have  very  little  conclusive 
value.  Accordingly,  as  it  is  the  purpose  of  this  laboratory  to  secure 
sufficient  data  to  eliminate,  so  far  as  possible,  the  personal  equation, 
we  frankly  stated  in  our  earlier  publication1  that  we  were  still  occupied 
in  "  overcoming  the  paucity  of  results  obtained  with  normal  infants," 
and  similar  statements  were  made  with  regard  to  the  new-born  infants. 
Our  observations  of  new-born  infants  were  begun  in  the  latter  part  of 
1913  and  were  freely  discussed  with  the  investigators  working  in  the 
same  field.  There  seems  to  have  been  a  disposition  on  the  part  of  some 
investigators  to  relieve  us  of  the  responsibility  of  interpreting  certain  of 
our  results;  consequently,  we  present  here  our  complete  data  in  regard 
to  the  character  and  amount  of  the  metabolism  of  105  new-born  infants, 
74  of  which  were  studied  within  24  hours  of  birth. 

EMBRYONIC  CONDITIONS. 

Although  the  interest  of  the  embryologist  in  the  prenatal  develop- 
ment of  the  infant  begins  at  the  moment  of  conception,  it  is  not  until 
the  fetus  has  reached  a  considerably  advanced  stage  of  development 
that  an  intelligent  interest  can  be  taken  in  its  metabolism.  Histological 
studies  show  that  the  composition  of  the  embryo  is  not  materially  dif- 
ferent from  that  of  the  adult  organism.  Food  is  carried  to  the  placenta 
by  the  blood  of  the  mother  and  we  have  no  reason  to  believe  that  there 
is  in  the  prenatal  life  any  marked  difference  between  the  mother  and 
the  fetus  in  the  character  of  the  katabolism.  On  the  other  hand, 
histological  studies2  do  show  that  there  is  in  the  embryo  a  relatively 
large  proportion  of  glycogen.  While  this  is  shown  microscopically, 
it  has  not  as  yet  received  verification  by  chemical  analysis.  At  the 
present  time,  therefore,  the  common  belief  in  a  large  supply  of  glycogen 
in  the  embryo  is  based  solely  upon  histological  studies,  made  almost 
entirely  on  animals,  and  it  is  well  known  that  the  results  of  histological 

Benedict  and  Talbot,  Am.  Journ.  Diseases  of  Children,  1914,  8,  p.  43. 

2Gierke,  Lubarsch-Ostertag's  Ergeb.  Jahrb.,  1907,  11  (2),  p.  880.  Also,  Lubarsch,  Virchow's 
Archiv,  1906, 183,  p.  188.  Most  of  the  work  has  been  done  on  animals,  with  the  single  exception 
of  that  by  Lubarsch.  Lubarsch  examined  a  9-weeks  human  embryo  and  a  4  to  5  months  human 
fetus,  and  concluded  that  the  amount  of  glycogen  varied  with  the  age  and  the  species.  The 
muscles  contain  a  considerable  amount  of  glycogen  even  in  the  embryo,  while  glycogen  is 
only  deposited  in  the  liver  in  later  embryonic  life.  Mendel  and  Leaven  worth  (Am.  Journ.  Physiol. , 
1907-8, 20,  p.  117)  add  to  Gierke's  extended  review  of  the  literature  on  the  subject. 


»* 

80  ll^H^J^I^y^OF   THE    NEW-BORN    INFANT. 

studies  and  chemical  analyses  do  not  necessarily  agree.1  It  is  gener- 
ally considered,  however,  that  the  fetus  has  a  larger  supply  of  glycogen 
in  proportion  to  its  weight  than  has  the  mother.  If,  as  we  believe, 
the  character  of  the  combustion  is  determined  in  large  measure  by  the 
character  of  the  available  food-supply,  it  is  not  inconceivable  that  there 
may  be  a  larger  combustion  of  glycogen  and  a  specific  fetal  katabolism. 
On  the  other  hand,  the  oxygen  and  food  are  obtained  from  the  blood  of 
the  mother,  and  while  the  fetus  may  be  glycogen-rich,  the  liver  of  the 
mother  is  likewise  glycogen-rich,  and  hence  it  may  be  unreasonable  to 
expect  a  specific  gaseous  metabolism  of  the  embryo  in  the  pre-natal  state. 
It  is  hardly  probable  that  with  our  present  technique  we  can  ration- 
ally interpret  the  character  of  the  katabolism  of  the  fetus  by  measuring 
the  gaseous  metabolism  of  the  mother  and  the  child  before  the  birth  of 
the  child,  and  the  mother  alone  after  delivery,  for  as  the  metabolism 
of  the  mother  is  very  much  greater  than  that  of  the  child,  a  differential 
method  is  liable  to  very  great  error. 

POST-NATAL  CONDITIONS. 

As  soon  as  the  child  is  born  all  of  the  conditions  are  changed.  Prior 
to  birth  the  fetus  is  living  on  a  rich  food-supply  which  is  brought  by  the 
maternal  blood.  Immediately  after  birth  this  supply  is  cut  off  and  no 
food  is  thus  derived  from  the  mother.  The  infant  then  begins  to 
starve,  that  is,  to  draw  upon  its  reserve  body-material  until  the  mother's 
breasts  secrete  enough  food  to  supply  its  demands.  We  may  properly 
ask,  what  is  this  reserve  and  how  does  it  influence  the  character  as 
well  as  the  totality  of  the  katabolism?  The  amount  of  the  material 
burned  we  know  is  determined  in  large  part  by  the  muscular  activity 
of  the  infant,  but  since  now  the  infant  must  live  (for  the  first  hours,  at 
least)  solely  upon  its  own  body-reserve,  the  character  of  the  material 
available  for  combustion  and  the  character  of  the  material  actually 
burned  present  a  new  interest. 

No  mammal  mother  is  so  completely  incapacitated  for  carrying  out 
the  duties  necessary  to  protect  and  nourish  her  young  during  the  first 
few  days  after  parturition  as  is  civilized  woman.  On  the  first  day  after 
birth,  the  mother  is  usually  absolutely  dependent  upon  the  ministra- 
tions of  others.  The  infant  must  likewise  share  this  dependency  upon 
others.  Even  the  natural  food-supply  of  the  parturient  mother  is  extra- 
ordinarily small,  for  the  total  fuel  value  of  the  colostrum  is  insufficient 
during  the  first  few  days,  even  under  the  most  favorable  circumstances.2 

We  may  question,  then,  is  the  new-born  child  automatically  adjusted 
to  this  state  of  affairs?  Is  the  body-supply  sufficiently  liberal  to  pro- 
vide for  the  draft  upon  it,  and  have  we  really,  therefore,  a  self-contained 
little  engine?  What  are  the  infant's  needs  for  the  first  few  days? 

'Rusk,  Proc.  Soc.  Exp.  Biol.  and  Med.,  1912, 10,  p.  21. 
2See  page  122. 


INTRODUCTION.  9 

First,  the  infant  must  keep  up  its  vitality.  In  the  prenatal  condition 
it  has  been  in  a  moist,  warm  medium,  with  no  loss  of  heat  by  radiation 
or  by  the  vaporization  of  water.  By  birth  it  is  suddenly  thrust  into 
a  much  less  moist  and  often  cold  environment.  It  is  currently  believed 
that  this  change  is  in  some  way  actually  beneficial,  since  it  acts  as  a 
stimulus  to  the  vital  activities  of  the  infant.  But  immediately  after 
birth  the  child  is  required  to  make  up  for  the  heat  lost  by  radiation, 
which  is  considerable,  and  for  that  used  in  the  vaporization  of  water 
from  the  body-surface.  In  the  few  days  subsequent  to  the  birth  the 
infant's  heat-regulating  mechanism  is  extremely  imperfect.  It  is  first 
called  into  play  as  soon  as  the  child  is  delivered.  A  bath  is  usually 
given  shortly  after  the  delivery,  which,  with  its  attendant  exposure 
of  the  body,  unquestionably  increases  the  heat  loss.  There  is,  however, 
almost  invariably  an  increased  heat-production  as  the  result  of  muscular 
activity  and  frequently  loud,  vigorous  crying. 

We  may  classify  the  new-born  infant's  needs  under  two  gross  cate- 
gories: first,  the  need  for  maintenance,  and  second,  the  need  for 
growth.  Since,  in  our  discussion,  we  are  interested  for  the  most  part 
in  the  consideration  of  the  metabolism  during  the  first  week  of  life,  we 
may  properly  at  this  time  omit  consideration  of  the  question  of  growth 
and  confine  ourselves  exclusively  to  the  maintenance  requirements.  The 
question,  then,  is :  Can  the  infant  in  the  first  week  of  life  obtain  sufficient 
nourishment  from  its  mother,  even  a  normal  mother,  to  maintain  its 
vital  activities  without  loss  of  body-substance?  An  examination  of  the 
records  of  body-weight  will  be  of  interest  in  this  connection,  for  a  loss 
in  weight,  if  any,  may  be  considered  a  crude  index  of  the  infant's  needs. 

LOSS  IN  BODY-WEIGHT. 

Shortly  after  birth  there  is  normally  a  very  considerable  loss  in  body- 
weight.  The  average  duration  of  this  loss  in  weight  is  2  to  3  days,  the 
length  of  time  depending  upon  when  the  mother's  milk-supply  is  suf- 
ficiently established  to  provide  the  infant  with  enough  nourishment  for 
its  needs.  If  an  infant  continues  to  lose  weight  after  the  fourth  day 
the  cause  must  be  pathological.  As  may  naturally  be  expected,  the 
time  and  amount  of  the  secretion  of  the  breast-milk  are  the  principal 
factors  in  determining  the  amount  of  weight  lost.  The  loss  of  weight 
varies  according  to  different  investigators,  but  usually  lies  between 
150  and  300  grams,1  with  an  extreme  high  figure  of  700  grams.2  A  loss 
of  even  400  to  500  grams  has  been  observed  with  infants  which  have 
shown  no  pathological  disturbance  at  the  time  or  later.  In  general, 
the  smaller  the  baby  is  at  birth,  the  greater  will  be  the  relative  propor- 
tion of  the  weight  lost,  the  usual  proportion  being  between  6  and  9  per 

Von  Reuss,  Die  Krankheiten  des  Neugeborenen,  Berlin,  1914,  p.  2. 

2Czerny  and  Keller,  Des  Kindes  Ernahrung,  Ernahrungsstorungen  und  Ernahrungstherapie, 
Leipsic  and  Vienna,  1906,  1,  p.  554. 


10  PHYSIOLOGY   OF   THE    NEW-BORN   INFANT. 

cent  of  the  birth-weight.  Trepper1  has  concluded  that  the  percentage 
loss  was  greatest  with  weak,  undeveloped  infants,  least  with  those  of 
average  weight,  increasing  again,  not  only  absolutely  but  relatively, 
with  large  infants  because  of  the  greater  trauma  during  birth. 

But  the  loss  in  body-weight  of  the  new-born  infant  may  not  be  taken 
as  an  index  of  its  physiological  needs  for  nourishment,  as  an  analysis 
of  the  character  of  this  loss  in  weight  shows  us  that  there  are  two 
distinct  causes:  (1)  mechanical  and  (2)  physiological. 

Within  a  few  hours  after  birth  the  infant  passes  urine  and  meconium 
and  at  times  regurgitates  allantoic  fluid  from  the  stomach.  No  one  of 
these  can  be  said  to  represent  a  loss  due  to  the  physiological  disintegra- 
tion of  body-substance,  but  they  should  all  be  classified  under  the  head 
of  mechanical  loss. 

Subsequently  there  is  a  loss  of  body-material  or  body-reserve  which 
should  be  considered  as  definitely  disintegrative.  When  a  previously 
nourished  organism  is  subjected  to  complete  inanition  or  withdrawal 
of  food,  there  is  in  all  cases  a  marked  loss  in  weight  during  the  first 
period  of  the  fast,  and  as  the  fast  progresses  the  loss  becomes  consider- 
ably less  per  unit  of  time.  This  is  strikingly  noted  in  experiments  with 
fasting  animals,  and,  indeed,  in  those  with  man,  and  receives  a  logical 
explanation  in  view  of  modern  studies  which  show  that  there  is  an  excess- 
ive water-loss  during  the  earlier  stages  of  inanition.  Exactly  the  same 
conditions  may  be  said  to  exist  in  the  case  of  new-born  infants.  Before 
birth  the  infant  was  in  a  moist  environment  and  the  body  was  therefore 
surcharged  with  water.  A  not  inconsiderable  amount  of  this  may  be 
lost  very  shortly  after  birth  through  vaporization  from  the  skin  and 
lungs,  particularly  when  active  crying  takes  place.  This  water  should 
be  considered  as  preformed  water  existing  in  the  body. 

But  the  most  important  physiological  loss  is  that  due  to  the  actual 
oxidation  of  body-substance  as  a  result  of  metabolism.  With  the  first 
moment  after  delivery  and  as  soon  as  the  lungs  have  become  filled  with 
air,  the  infant  begins  to  oxidize  body-substance,  this  material  being 
chiefly  fat,  with  some  protein  and  some  carbohydrate.  This  material 
is  carried  off  in  the  form  of  carbon  dioxide  and  of  oxidized  organic 
hydrogen,  and  thus  contributes  its  quota  to  the  physiological  loss. 

Since  the  loss  of  meconium,  allantoic  fluid,  and  urine,  and  even  of 
preformed  water,  is  not  accompanied  by  energy  transformations  and 
the  liberation  of  heat,  we  may  estimate  the  true  physiological  loss  by 
determining  the  energy  loss  either  directly  or,  what  is  more  practicable, 
by  the  indirect  method  of  measuring  the  carbon-dioxide  output  and  the 
oxygen  consumption. 

Although  it  is  a  popular  conception  that  the  new-born  infant  has  a 
very  much  larger  metabolism  than  has  the  adult,  evidence  that  we 

lrTrepper,  Ueber  die  Gewichtsabnahme  der  Neugeborenen,  Inaug.  Diss.,  Giessen,  1913. 


INTRODUCTION.  11 

have  already  published1  in  discussing  an  entirely  different  subject, 
namely,  the  metabolism  per  square  meter  of  body-surface,  shows  that 
new-born  infants  have  a  relatively  low  heat-production  per  square  meter 
of  body-surface.  The  calorific  needs  for  these  infants  may  therefore 
be  legitimately  considered  as  extraordinarily  low.  If  we  compute  the 
calories  required  for  a  new-born  infant  on  the  basis  of  the  experiments 
previously  published  by  us,  we  find  that  the  daily  heat-output  of  a 
quiet,  resting  new-born  infant  of  approximately  3.76  kilograms  cor- 
responds to  the  oxidation  of  about  17  grams  of  fat.  Since  the  total 
loss  in  weight  during  the  first  few  days  is  200  to  300  grams,  it  can  be 
seen  that  only  a  small  proportion  of  this  loss  can  consist  of  organized 
body- tissue,  such  as  fat.  Even  if  the  entire  energy  output  were  derived 
from  the  combustion  of  carbohydrate,  the  amount  katabolized,  i.  e.} 
approximately  40  grams,  or  about  twice  the  amount  corresponding  to 
the  katabolism  of  fat,  would  still  be  too  small  to  account  for  this  loss 
in  body-weight.  The  relatively  small  amounts  of  protein  katabolized 
may  properly  be  disregarded  in  discussing  this  phase  of  the  total 
metabolism.  Hence  the  only  other  alternative  we  deal  with  here  is 
the  loss  of  a  large  amount  of  water. 

In  the  foregoing  considerations,  however,  the  assumption  is  made 
that  the  infant  is  undergoing  complete  starvation.  As  a  matter  of  fact, 
a  certain,  although  admittedly  deficient,  amount  of  nourishment  is 
obtained  from  the  small  amount  of  colostrum  available.  This  would, 
in  part  at  least,  tend  to  retard  any  physiological  loss  in  weight  and  a 
consideration  of  this  fact  only  accentuates  the  contention  that  the  loss 
in  weight,  per  se,  can  not  be  an  accurate  index  of  the  food  require- 
ment of  the  new-born  infant. 

Benedict  and  Talbot,  Carnegie  Inst.  Wash,  Pub.  No.  201,  1914,  p.  157;  also,  Am.  Journ. 
Diseases  of  Children,  1914,  8,  p.  1. 


12 


PHYSIOLOGY   OF   THE   NEW-BORN   INFANT. 


EARLIER  RESEARCHES  WITH  NEW-BORN  INFANTS. 

Considering  the  marked  physiological  loss  in  weight  during  the 
first  week  of  life,  the  rapidly  changing  character  of  the  nourishment,  and 
the  supposed  imperfect  heat  regulation  of  the  new-born  infant,  together 
with  the  fact  that  all  human  beings  must  pass  through  the  experiences 
of  this  period,  it  is  surprising  that  so  little  evidence  regarding  both  the 
character  and  the  amount  of  human  metabolism  during  the  first  week  of 
life  is  available.  There  are  almost  no  reliable  observations  on  the 
character  of  the  katabolism  and  the  majority  of  observations  on  the 
amount  of  metabolism  are,  in  the  light  of  present-day  technique, 
seriously  vitiated  by  the  fact  that,  at  the  time  the  researches  were 
made,  the  importance  of  complete  muscular  repose  on  the  part  of  the 
infants  was  but  imperfectly  realized. 

OBSERVATIONS  BY  MENSI. 

Although  Forster,1  in  1877  studied  the  carbon-dioxide  output  of  an 
infant  14  and  60  days  after  birth,  and  10  years  later  Langlois2  studied 
the  heat-production  of  an  infant  15  days  old,  it  was  not  until  the  research 
of  Mensi3  in  1894  that  we  find  any  observations  on  the  gaseous  metab- 
olism or  heat-production  of  infants  during  the  first  week  of  life. 

As  a  matter  of  fact,  Mensi'  s  infants  were  all  somewhat  under  the 
normal  weight  of  a  new-born  infant,  and  while  the  oxygen  consumed  per 
kilogram  per  minute,  as  reported  by  Mensi,  appears  to  be  reasonably 
uniform,  the  extraordinarily  low  respiratory  quotients  noted  by  him 
still  leave  the  experimental  procedure  somewhat  in  doubt.  The  appa- 
ratus used  by  Mensi  has,  so  far  as  we  know,  never  been  described. 
After  a  number  of  efforts  we  have  finally  been  able,  through  the  kind- 
ness of  Professor  G.  Fano  of  Florence  and  Professor  Herlitzka  of  Turin, 


,  Amtlicher  Bericht  der  50.  Versammlung  deutsch.  Naturforscher  u.  Aerzte  in  Munchen, 
Munich,  1877,  p.  355.  Supplementary  data  regarding  these  two  observations  were  given  in  a  per- 
sonal communication  to  Professor  Magnus-Levy  and  published  by  him  in  the  Archiv  f  .  Anat.  u. 
Physiol.,  1889,  Suppbnd.,  p.  314.  According  to  Professor  Forster,  the  data  were  obtained  on  a 
girl,  '  '  bei  ziemlicher  Ruhe."  Although  the  infant  was  older  than  those  included  in  our  own  study, 
we  consider  the  material  of  sufficient  importance  to  give  the  following  tabular  data,  which  were 
published  by  Magnus-Levy  regarding  Forster's  observations: 


Carbon 

Carbon  dioxide 

Carbon 

Carbon  dioxide 

Age. 

Weight. 

dioxide 
eliminated 

eliminated  per 
kilogram  per 

dioxide 
eliminated 

eliminated  per 
kilogram  per 

per  hour. 

hour. 

per  minute. 

minute. 

days. 

kilos. 

gm. 

gm. 

c.c. 

c.c. 

14 

2.70 

2.52 

0.93 

21.40 

7.89 

60 

3.78 

3.68 

0.97 

31.07 

8.22 

2Langlois,  Journ.  de  1'Anat.  et  de  Physiol.,  1887,  23,  p.  400.  Langlois'  observation  on  an  infant 
15  days  old  was  only  incidental  and,  in  view  of  the  known  errors  of  the  calorimeter  employed,  the 
values  can  have  only  an  historic  interest. 

3Mensi,  Giorn.  d.  R.  Accad.  di  Med.  di  Torino,  1894,  57,  p.  301.  An  abstract  of  Mensi's  obser- 
vations was  given  in  our  earlier  publication.  See  Benedict  and  Talbot,  Carnegie  Inst.  Wash. 
Pub.  No.  201,  1914,  p.  14. 


EARLIER   RESEARCHES   WITH    NEW-BORN    INFANTS.  13 

to  secure  information  from  Mensi  regarding  the  apparatus  and  the 
technique  used  in  the  observations.  The  infant  was  placed  under  a 
bell  in  which  air  was  circulated.  The  carbon-dioxide  output  was  deter- 
mined by  barium  hydroxide,  while  the  oxygen  consumption  was  found 
by  measuring  the  amount  used  from  a  flask  of  known  capacity  in  replac- 
ing the  oxygen  consumed  by  the  infant.  The  principle  of  the  apparatus 
appears  to  be  essentially  that  of  Regnault  and  Reiset. 

OBSERVATIONS  BY  SCHERER. 

Perhaps  no  research  on  the  gaseous  metabolism  of  infants  is  more 
frequently  cited  as  being  the  earliest  and  of  the  greatest  significance 
than  is  that  of  Scherer1  in  the  laboratory  of  Professor  Mares  in  Prague. 
As  pointed  out  in  our  earlier  consideration  of  these  experiments,2  the 
extraordinarily  low  respiratory  quotients  found  by  the  investigator 
lead  one  to  doubt  the  accuracy  of  the  determination  of  the  gaseous 
metabolism.  In  the  latter  part  of  his  article,  Scherer  discusses  the 
protocols  of  one  experiment,  which  he  gives  in  detail,  and  points  out 
the  fact  that  Mares  considered  that  the  increase  in  the  nitrogen  of 
the  air  inside  the  chamber  should  be  taken  as  an  indication  of  the  accu- 
racy of  the  experiment,  since  the  smaller  the  nitrogen  accumulation, 
the  more  accurate  is  the  experiment. 

Unusual  attention  was  paid  in  the  Prague  laboratory  to  the  possi- 
bilities of  leaks  into  or  out  of  the  respiration  system,  and  the  earlier 
work  in  Pfliiger's  laboratory  was  keenly  criticized  by  Mares3  in  the 
original  description  of  his  apparatus  for  studying  the  metabolism  of 
animals  during  hibernation.  In  this  Bohemian  monograph  Mares 
devotes  several  pages  to  a  discussion  of  the  possibilities  of  error  due 
to  leaks,  to  the  accumulation  of  nitrogen,  and  to  the  role  the  nitrogen 
may  play  in  the  total  metabolism,  and  gives  a  number  of  arguments 
for  and  against  the  belief  that  free  nitrogen  rises  from  protein  disin- 
tegration. It  is  surprising,  therefore,  to  find  that  Scherer  assumed 
the  percentage  composition  of  the  compressed  oxygen  used  by  him 
to  be  that  determined  by  an  old  analysis.  This  point  can  best  be 
considered  in  connection  with  the  keen  criticism  of  Scherer  ?s  experi- 
ments by  Hasselbalch  in  the  excellent  paper  which  will  be  presented 
somewhat  later  in  this  report. 

Scherer  made  55  experiments  in  the  spring  and  summer  and  30 
experiments  in  the  winter,  each  experiment  being  about  2  hours  long. 
A  considerable  number  of  these  experiments  were  with  infants  7  days 
old  or  under,  namely,  24  experiments  in  the  summer  and  7  experiments 
in  the  winter.  It  is  most  unfortunate  that  at  this  period  in  the  develop- 
ment of  the  respiration  apparatus  in  the  Prague  laboratory  control 


T  Jahrb.  f.  Kinderheilk.,  1896,  N.  F.,  43,  p.  471. 
2Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1914,  p.  14. 
3Mares,  Arch,  bohemes  de  med.,  1889,  2,  p.  458. 


14  PHYSIOLOGY   OF  THE   NEW-BORN   INFANT. 

tests  were  not  made  with  burning  alcohol.  Although  such  tests  are 
cited  in  the  reports  of  later  investigations  in  this  laboratory,  Scherer 
gives  no  description  of  control  tests  made  by  him. 

OBSERVATIONS  BY  BABAK. 

The  next  research  on  this  subject  published  from  the  Prague  labora- 
tory was  that  of  Babdk,1  which  appeared  in  Bohemian  in  1901  and  in  a 
somewhat  abridged  form  in  German  in  1902.  Babdk's  investigations 
dealt  primarily  with  the  study  of  the  heat  regulation,  the  Bohemian 
paper  being  prefaced  by  an  extended  consideration  of  theoretical 
points  involved  in  the  discussion  of  the  chemical  and  physical  heat 
regulation;  evidently  this  was  the  whole  trend  of  his  discussion  and  his 
experimental  research,  his  interest  in  the  gaseous  metabolism  of  new- 
born infants  being  only  secondary. 

Babdk  used  a  respiration  apparatus  of  the  Regnault-Reiset  type, 
which  was,  indeed,  the  apparatus  originally  employed  by  Scherer  but 
later  somewhat  modified  by  the  attachment  of  calorimetric  devices 
on  the  d'Arsonval  principle.  The  control  tests,  which  were  made  by 
the  burning  of  alcohol,  are  reported  to  give  an  accuracy  of  2  per  cent 
within  theory  for  the  oxygen  consumption  and  6  per  cent  within  theory 
for  the  carbon-dioxide  production.  This  large  error  in  the  carbon 
dioxide  is,  we  believe,  unique  with  the  Regnault-Reiset  type  of  respira- 
tion apparatus,  for  with  all  of  the  apparatus  that  we  have  thus  far 
investigated  we  have  found  that  the  determinations  of  the  carbon 
dioxide  are  usually  extraordinarily  exact,  practically  all  of  the  errors 
falling  upon  the  oxygen.  Since  no  protocols  are  given  by  Babdk, 
either  in  the  German  paper  or  in  the  Bohemian  paper,  further  intelli- 
gent discussion  of  the  technique  is  impossible.  In  all  63  experiments 
were  made  with  7  infants,  ranging  in  age  from  1  to  8  days.  No  records 
were  published  for  these  infants  of  the  degree  of  activity  or  of  the  pulse- 
rate.  We  can  not,  therefore,  compare  the  total  metabolism  as  measured 
by  this  type  of  apparatus  with  the  results  of  modern  researches. 

As  the  alcohol  control  tests  of  Babdk's  calorimeter  never  showed  an 
extraordinarily  high  degree  of  accuracy,  and  as  Babdk's  problem  was 
simply  to  determine  the  temperature  regulation  of  the  new-born 
infant,  it  is  not  surprising  that  in  the  German  article  he  gives  but 
a  few  words  to  the  discussion  of  the  respiratory  quotient,  only  making 
the  statement  that,  like  Scherer,  he  found  the  respiratory  quotient 

^abak,  Rozp.  C.  Akad.  Cisafe  Frantiska  Josef  a,  Tfida  II,  Rodnik  X,  6fslo  I,  1901,  and  Archiv 
f .  d.  ges.  Physiol.,  1902, 89,  p.  154.  The  reference  to  the  German  publication  of  Babdk's  researches 
was  inadvertently  omitted  from  our  two  previous  communications.  (See  Benedict  and  Talbot, 
Carnegie  Inst.  Wash.  Pub.  No.  201,  1914,  and  Am.  Journ.  Diseases  of  Children,  1914,  8,  p.  1.) 
At  the  time  the  literature  was  being  assembled  we  were  awaiting  a  complete  translation  of  the 
original  Bohemian  article,  and  as  this  could  not  be  finished  prior  to  publication  it  was  not  inserted. 
The  absence  of  the  German  reference  was  clearly  an  omission.  At  this  point  we  would  like  to 
state  that  the  Bohemian  article  has  been  translated  by  Miss  B.  Haderbolets,  the  Bohemian  trans- 
lator of  the  Nutrition  Laboratory,  and  a  copy  is  on  file  in  the  laboratory. 


OBSERVATIONS   BY   HASSELBALCH.  15 

to  be  somewhat  lower  in  winter  than  in  summer.  In  the  Bohemian 
article  we  find  a  somewhat  more  extended  discussion  of  his  results, 
inasmuch  as  Babak  points  out  that  the  respiratory  quotient  does  not 
show  regularity,  this  being  largely  due  to  variations  in  the  carbon- 
dioxide  determinations.  The  majority  of  the  low  values  for  the 
respiratory  quotients  were  found  during  the  low  temperature  of  winter, 
and  Babak  concludes  that  since  similar  observations  were  obtained 
with  rabbits  he  can  corroborate  the  discovery  of  Scherer  that  in  winter 
assimilation  is  greater  than  disassimilation,  or  that  anabolism  is  greater 
than  katabolism. 

OBSERVATIONS  BY  HASSELBALCH. 

In  1904  Hasselbalch,1  publishing  in  a  remote  place,  presented  a  most 
interesting  paper  on  respiration  experiments  with  new-born  infants. 
At  the  time  of  going  to  press  with  our  earlier  publication,  this  Danish 
contribution  was  in  process  of  translation,  and  hence  it  was  not  then 
cited  by  us.  Upon  the  completion  of  the  translation,  for  which  it  is 
a  pleasure  to  thank  Miss  Alice  Johnson,  of  the  Nutrition  Laboratory 
staff,  and  Dr.  M.  N.  Smith-Petersen,  of  the  Peter  Bent  Brigham 
Hospital,  we  are  so  impressed  with  the  accuracy  of  the  technique  and 
the  clear-cut  conception  of  Hasselbalch' s  conclusions  that  we  feel  it  is 
incumbent  upon  us  to  make  this  material  available  to  readers  in  other 
than  Danish,  and  hence  it  is  here  reprinted.  We  wish  to  express  our 
thanks  to  Professor  Hasselbalch  for  his  kindness  in  looking  over  the 
manuscript  and  making  some  slight  alterations  in  the  phraseology  of 
the  translation. 

Hasselbalch,  Respirationsfors^g  paa  nyf0dte  B0rn,  Bibliotek  for  Laeger,  Copenhagen,  1904, 
8,  p.  219. 


16  PHYSIOLOGY   OF   THE    NEW-BORN   INFANT. 

RESPIRATION  EXPERIMENTS  WITH  NEW-BORN  INFANTS. 
BY  K.  A.  HASSELBALCH. 

The  desirability  of  carrying  out  total  metabolism  experiments  on 
healthy  and  sick  infants  with  a  view  to  obtaining  information  regarding 
the  adequate  nourishment  of  the  infant  is  very  evident.  So  long  as  it 
is  not  an  established  fact  how  the  healthy  and  normally-nourished  infant 
utilizes  the  fat  and  carbohydrate  of  milk,  so  long  every  therapeutic  treat- 
ment of  the  fatal  conditions  in  pedatrophia  is  absolutely  guesswork,  and 
so  long  the  composition  of  the  countless  strength-giving  foods  for 
artificially  nourishing  infants  is  based  on  the  roughest  empiricism  by 
observing  the  changes,  if  any,  in  the  curve  of  the  body-weight. 

While  the  present  paper  does  not  report  experiments  on  total  metabo- 
lism, a  study  of  the  respiratory  exchange  of  the  new-born  infant  is  also 
of  considerable  interest.  In  the  first  place,  the  amount  of  the  respira- 
tory exchange,  because  of  its  considerable  excess  over  the  nitrogen 
exchange,  may  be  used  as  an  expression  of  the  amount  of  the  total 
metabolism,  and  in  the  second  place  the  respiratory  quotient  throws 
light  on  the  substances  oxidized  in  a  given  period  of  time. 

It  is  generally  believed  that  a  young  individual  has  a  greater  metabo- 
lism, per  kilogram  of  body- weight  than  the  adult,  because  of  its  greater 
surface  in  relation  to  its  body-weight  and  because  it  is  growing.  I  shall 
not  enter  into  a  discussion  of  the  rather  contestable  "law  of  surface 
area"  which  is  the  subject  of  so  much  dispute.  My  experiments 
can  not  be  used  to  support  such  a  discussion  successfully,  for  it  is 
rather  difficult  with  young  children  to  represent  fairly  the  same  external 
and  internal  experimental  conditions  as  are  represented  by  other  inves- 
tigators in  their  respiration  experiments  with  adults.  In  one  respect 
only  can  my  experiments  give  enlightenment,  that  is,  as  to  the  influence 
of  exercise  on  the  amount  of  the  metabolism.  From  experiments 
during  which  the  infant  slept  quietly  I  have  obtained  material  whereby 
I  could  form  my  own  point  of  view  in  regard  to  the  dogma  concerning 
the  relatively  large  metabolism  of  the  infant.  If  it  is  possible  from  the 
experiments  to  come  to  an  approximate  conclusion  concerning  the 
amount  of  the  metabolism  of  the  new-born  sleeping  infant,  this  conclu- 
sion has  a  special  interest  as  bearing  directly  on  the  fetal  life.  In  the 
embryonic  condition  it  is  well  known  that  the  metabolism  per  unit  of 
body-weight  is  as  great  as  with  the  grown  individual  of  the  same  species. 

The  respiratory  quotient,  obtained  as  soon  as  possible  after  birth, 
gives  information  as  to  the  approximate  composition  of  the  new-born 
infant's  fuel  material  and  permits  an  assumption  as  to  its  composition 
in  the  embryonic  state.  The  breast-fed  infant— and  the  infant  that 
directly  after  birth  has  been  given  the  spoonful  of  cane-sugar  solution 
traditional  in  Denmark1 — give  the  experimenter  some  idea  of  the  time 

*The  following  information  regarding  this  practice  is  kindly  supplied  by  Hasselbalch  in  a 
personal  communication:  "The  midwife  gives  the  child  a  teaspoonful  or  two  of  a  weak  cane-sugar 
solution  (strength  of  solution  quite  accidental)  after  the  child  is  washed  and  before  it  is  put  to  bed. 
We  suppose  the  reason  to  be  that  the  child  should  not  be  starving  until  the  mother  has  milk  enough 
for  it.  Generally  the  administration  of  cane-sugar  is  not  repeated,  as  the  role  of  the  midwife  is 
now  over  and  the  nurse's  work  begins." 


OBSERVATIONS   BY   HASSELBALCH.  17 

required  for  the  absorption  and  oxidation  of  the  three  nutrients  in  the 
food — the  protein,  fat,  and  carbohydrate. 

The  only  complete  respiration  experiments  on  new-born  infants 
known  to  me  were  undertaken  first  at  Prague  under  the  direction  of 
Mares  by  Scherer1  and  Babak.2  The  experiments  of  Babak  on  the  respi- 
ratory exchange  are  only  a  link  in  the  investigation  of  the  new-born 
infant's  heat  regulation.  The  surprising  result  of  both  these  investi- 
gators' experiments  is  this,  that  not  only  after  birth,  but  even  with 
infants  several  weeks  old,  an  unusually  low  respiratory  quotient  was 
found.  Scherer  reports  55  summer  experiments  with  respiratory 
quotients  ranging  from  0.567  to  0.898;  in  27  instances  the  quotients 
are  under  0.70,  a  quotient  which,  for  the  grown  individual,  is  the  lowest 
imaginable,  at  least  for  rather  long  periods  of  time.  His  30  winter 
experiments  show  but  one  quotient  over  0.70;  the  lowest  is  0.493,  the 
highest  0.717.  Babak's  experiments  generally  show  a  higher  quotient, 
but  0.51  is  not  uncommon  with  him. 

To  explain  these  low  quotients,  which  are  ordinarily  found  only  with 
hibernating  animals,  Scherer  has  to  resort  to  the  explanation  generally 
assumed  for  these  animals,  i.  e.,  an  incomplete  burning  of  food  material, 
whereby  the  oxygen  taken  in  does  not  leave  the  organism  in  its  entirety 
as  carbon  dioxide,  but  to  some  extent  is  stored  up  in  the  form  of  unstable 
compounds.  Scherer,  in  attempting  to  explain  the  significance  of  this 
saving  of  oxygen  in  infancy,  refers  to  the  "  excess  of  anabolism  over 
katabolism";  but  this  conclusion  does  not  hold  true.  In  the  fetal  life, 
then,  one  must  also  expect  low  quotients,  lower  than  with  the  free  oxi- 
dation of  the  embryo's  food  material.  But  the  chicken  embryo  burns 
fat  and  has  a  fat  quotient,  0.71 ;  the  guinea-pig  embryo  has  a  carbo- 
hydrate quotient3  of  1.00.  The  snake  embryo  has  a  mixed  quotient, 
about  0.85,  while  with  the  silk-worm  embryo4  the  respiration  takes 
place  with  a  diminution  of  both  fat  and  carbohydrate,  which  naturally 
would  result  in  a  quotient  between  0.7  and  1.0. 

The  hypothesis  presented  by  Farkas,5  partly  in  reference  to  the  fat 
quotient  with  the  bird  embryo  and  partly  in  reference  to  Scherer's  and 
Babak's  low  quotients  with  new-born  infants,  "wahrend  der  embryo- 
nalen  Entwicklung  und  in  den  ersten  Stunden  des  Lebens  iiberwiegend 
Fett  verbrannt  wird,"  may  be  disputed.  The  different  animal  classes 
can  not  be  expected  to  nourish  their  embryos  with  the  same  material; 
that  they  do  not  do  this  has  already  been  mentioned,  and  Farkas  him- 
self brings  forward  a  new  example  to  demonstrate  this  point. 

In  view  of  the  doubtful  respiratory  quotients  found  by  Scherer  and 
Babak,  we  must  reject  in  advance  Scherer's  second  conclusion  concern- 
ing the  amount  of  the  respiratory  exchange.  Eighty-five  experiments 
are  mentioned,  not  with  the  same  child,  but  with  different  children  at 
different  times.  From  this  material,  without  taking  into  consideration 
the  child's  condition  during  the  experiment,  such  as  movements,  crying, 

Scherer,  Jahrb.  f.  Kinderheilk.,  1896,  N.  F.,  43,  p.  471. 

2Babak,  Archiv  f.  d.  ges.  Physiol.,  1902,  89,  p.  154. 

3Bohr,  Vidensk.  Selsk.  Forh.,  1900. 

4Farkas,  Archiv  f.  d.  ges.  Physiol.,  1903,  98,  p.  490.  'Farkas,  loc.  cit.t  p.  517. 


18  PHYSIOLOGY   OF  THE   NEW-BORN   INFANT. 

digestion,  etc.,  Scherer  and  Babdk  draw  the  following  quite  unjusti- 
fiable conclusion:  "Die  Kohlensaureproduction  und  der  Sauerstoff- 
verbrauch  shaken  beim  Neugeborenen  etwas  in  den  ersten  Stunden 
nach  der  Geburt  bis  ung.  zur  neunten  Stunde,"  etc.  If  a  new-born 
infant  kicks  and  cries  soon  after  birth,  is  afterwards  quiet  and  sleeps 
almost  to  the  ninth  hour,  then  wakes  and  is  laid  at  the  breast,  the  results 
obtained  would  nearly  agree  with  the  quotation  given  above,  but  other- 
wise not.  Speck,1  a  well-trained  subject  for  physiological  experiments, 
tripled  his  respiratory  exchange  by  doing  considerable  work  with  one 
arm.  So  great  is  the  influence  of  muscular  contractions  upon  metabo- 
lism that  the  arrangement  of  a  schedule  like  the  one  indicated  above  is 
rather  a  waste  of  time. 

Scherer  and  Babdk  have  worked  with  the  same  respiration  apparatus. 
That  their  results  agree  quite  well,  therefore,  is  but  natural.  If  their 
results  are  incorrect,  as  I  must  assume  after  carrying  out  my  own  experi- 
ments, this  can  not  be  due  to  the  inaccuracy  of  their  methods  (although 
the  limit  of  error  of  6  per  cent  for  carbon  dioxide  is  quite  large,  the  res- 
piratory quotient  can  in  a  given  instance  vary  from  0.65  to  0.60),  but 
must  have  its  reason  in  a  systematic  error.  I  refer  to  Scherer's  descrip- 
tion of  his  experiments,  from  which  it  is  clear  that  in  the  closed  respiration 
apparatus  after  the  experiment  there  may  be  found  an  increase  of  541 
C.c.  beyond  the  calculated  nitrogen  quantity;  the  oxygen  consumed  is 
replaced  from  an  oxygen  bomb;  the  oxygen  introduced  into  the  chamber 
is  not  analyzed  for  its  purity,  but  is  assumed  from  "  Hoppe-Seyler's 
analysis"  of  the  same  manufacture  to  contain  4  per  cent  nitrogen;  if, 
in  reality,  it  contains  over  four  times  as  much  (which  is  perhaps 
unreasonable  but  always  possible),  this  would  explain  the  finding  of 
541  c.c.  of  nitrogen  in  excess.  If  on  this  basis  a  correction  is  made 
in  the  above  case,  the  quotient  rises  from  0.63  to  0.73. 

I  do  not  dare  insist  that  this  explanation  is  very  probable;  from  the 
account  of  the  experiment,  however,  I  find  no  other.  At  any  rate,  I 
may  say  that  a  method  with  such  large  sources  of  error  is  too  crude  to  be 
compared  with  mine,  which  has  given  especially  accurate  results  in  the 
hands  of  numerous  investigators.  My  method  of  experimentation  is 
given  herewith: 

The  atmospheric  air  from  outside  is  drawn  through  a  water  gas-meter,  and  from  there 
through  a  large  spiral  lead  pipe,  where  it  is  warmed  to  the  experimental  temperature.  The 
infant  lies  naked  in  a  15-liter  respiration  chamber,  which  is  placed  within  a  couveuse.  The  air 
is  sent  into  one  end  of  the  respiration  chamber  at  the  top,  passes  out  below  at  the  opposite 
end,  and  through  a  flask  where  the  moisture  of  the  expired  air  and  the  perspiration  is  con- 
densed. After  this  the  air-current  is  passed  into  a  simple  sampling  apparatus,  consisting  of 
a  mercury  receptacle  closed  with  three-way  taps,  from  which  the  mercury  can  run  out  in  a 
thin  stream  during  an  experiment.  By  this  means  almost  continuous  samples  of  the  air- 
current,  each  with  a  volume  of  70  c.c.,  may  be  obtained;  50  c.c.  of  the  sample  are  used  immedi- 
ately for  an  analysis  in  a  Pettersson  apparatus  (with  potassium  pyrogallate).  The  air  is 
sucked  over  the  child  by  means  of  a  water-suction  pump;  the  speed,  which  is  sufficiently  even 
for  our  purpose,  with  variations  never  over  3  per  cent,  is  regulated  according  to  the  percent- 
age of  carbon  dioxide  one  desires  in  the  respiration  chamber.  The  samples  of  air  are  not 
taken  until  the  infant  has  remained  in  the  air-current  so  long  that  we  can  assume  a  uniform 
composition,  i.  e.,  when  three  times  its  own  volume  of  air  has  been  passed  out  of  the  respira- 

,  Physiologic  des  menschlichen  Athmens,  Leipsic,  1892,  p.  82. 


OBSERVATIONS   BY   HASSELBALCH.  19 

tion  chamber,  after  at  least  12  to  15  minutes  or  longer,  according  to  circumstances.  The 
atmospheric  air  is  analyzed  either  on  the  day  of  the  experiment,  or,  in  case  of  evening 
and  night  experiments,  the  following  morning.  (The  occasionally  rather  insignificant  vari- 
ations in  the  composition  of  the  atmosphere  during  the  experiments  is  without  influence 
on  the  results,  so  that  now  and  then  an  atmospheric  analysis  is  omitted.  I  have  then  made 
my  calculations,  using  the  preceding  day's  analysis.)  From  the  percentage  composition  of 
the  air  before  and  after  it  passes  into  the  chamber  the  respiratory  quotient  is  estimated 
(with  a  small  reduction  based  on  the  supposition  that  the  nitrogen  does  not  take  part  in  the 
respiratory  exchange)  and  from  the  quantity  of  air  which  has  circulated  in  the  respiration 
chamber  during  the  experiment  and  which  has  been  determined  by  the  gas-meter,  the  abso- 
lute amount  of  the  metabolism  is  calculated,  with  a  reduction  for  pressure  and  temperature. 

The  temperature  during  the  experiment  as  recorded  by  a  thermometer  inside  the  respira- 
tion chamber,  fastened  firmly  to  the  under  side  of  the  glass  top  or  ceiling  of  the  chamber, 
varies  during  the  experiment  between  31°  and  35°  C.  The  intention  was  to  supply  perfect 
physiological  conditions  for  the  infants.  Since,  as  a  rule,  they  had  been  submitted  to  the 
customary  bath  and  had  a  particularly  low  temperature  previous  to  the  experiment,  the  body 
temperature  rose  sometimes  several  degrees,  but  never  above  normal.  This  rise  in  tempera- 
ture occurred  almost  entirely  during  the  15  minutes  that  preceded  the  experiment  proper, 
so  that  the  temperature  of  the  child  (see  in  tables  the  last  figures  under  "  Body  temperature") 
can  be  considered  as  nearly  constant  during  the  experiment. 

The  degree  of  humidity  in  the  air  is  also  physiological,  since  the  inspired  air,  saturated 
with  moisture  at  the  temperature  of  the  gas-meter  (15°  to  20°  C.),  is  afterwards  warmed  to 
about  32°  C.  before  it  is  inspired.  The  duration  of  an  experiment  is  from  22  to  24  minutes 
for  each  single  determination.  As  regards  the  accuracy  of  the  method,  even  if  the  greatest 
possible  errors  in  analyses  are  made  (according  to  numerous  double  determinations  of  the 
atmospheric  air),  this  could  alter  the  respiratory  quotient  only  1  or  2  in  the  third  decimal 
place.  The  weights  of  the  children  can  not  be  counted  on  to  give  a  greater  accuracy  than 
=fc25  grams;  partly  for  this  reason  and  partly  because  the  limit  of  error  for  the  reading  of  the 
gas-meter  is  ^0.5  per  cent,  the  error  in  the  determination  of  the  amount  of  the  metabolism 
per  kilogram  of  body-weight  and  per  hour  may  be  counted  as  =fc2  per  cent  of  the  reported 
value. 

When  we  consider  that  the  respiratory  quotient  of  the  guinea-pig 
embryo  is  about  1.0,  even  when  that  of  the  mother  animal  is  consider- 
ably lower,  it  is  natural  to  expect  that  the  new-born  infant,  which  is 
born  with  a  greater  or  less  store  of  glycogen  in  its  liver,  would  live  exclu- 
sively at  the  expense  of  this  supply  in  the  first  hours  of  its  life  and 
accordingly  give  a  carbohydrate  quotient.  This  should  be  all  the  more 
true,  the  shorter  the  interval  between  the  birth  of  the  child  and  the 
beginning  of  the  experiment. 

From  table  1,  in  which  6  respiration  experiments  with  new-born 
infants  weighing  over  3,000  grams  are  arranged  chronologically,  it  is 
evident  that  the  relationship  is  not  quite  so  simple.  The  youngest 
infant,  which  was  45  minutes  old  at  the  beginning  of  the  experiment, 
and  one  of  the  two  oldest,  which  was  2  hours  old,  show  quotients  of 
approximately  1.0,  but  in  experiments  3,  8,  and  7  a  mixed  exchange 
takes  place,  in  which  carbohydrates  are  chiefly  concerned;  in  experi- 
ment 12  we  find  a  pure  albumin  quotient,  which  can  also  originate  from 
the  burning  of  much  fat  and  few  carbohydrates. 

If  we  now  examine  table  1  more  closely,  we  see  quickly  that  the  sub- 
ject of  experiment  2,  with  a  pure  carbohydrate  quotient,  is  recorded  as 
"fat  and  strong";  its  weight  is  also  striking  in  comparison  with  its 
length  (3,650  grams  to  51  cm.).  Although  in  experiment  9  no  general 
impressions  of  the  infant's  condition  are  recorded,  it  is  obvious  from  the 
weight  and  height  that  this  was  also  a  particularly  well-nourished 


20 


PHYSIOLOGY   OF   THE   NEW-BORN   INFANT. 


child.  At  the  other  extreme  is  the  infant  in  experiment  12,  who,  with 
a  very  low  quotient,  is  heavy,  but  with  a  disproportionate  length  and 
consequently  thin.  If,  then,  having  the  condition  of  nourishment  in 
mind,  we  examine  the  remaining  experiments,  it  appears  for  the  present 
as  if  the  better  nourished  the  infant  is  the  nearer  to  1  is  the  respiratory 
quotient  of  the  new-born  fasting  infant  in  the  first  hours  after  birth.  We 
will  discuss  later  the  possible  influence  of  the  other  experimental 
conditions  on  the  quotient.  If  these  values  are  correct  the  period  of 
time  after  birth  affects  the  results  in  such  a  manner  that  with  the 
same  infant  in  two  consecutive  determinations  the  quotient  falls  from 
experiment  to  experiment. 

TABLE  I.1 


Carbon- 

dioxide 

Experi- 
ment 
No. 

Sex. 

Body- 
weight. 

Height. 

Age. 

Temperature 
of  air  in 
apparatus. 

Body-tempera- 
ture (rectal). 

Carbon- 
dioxide 
in  air  of 
cham- 

elimina- 
tion per 
kilogram 
per  hour 

Respir- 
atory 
quo- 

tiont 

ber. 

at  0°  C. 

tlclll'. 

and  760 

mm. 

gin. 

cm. 

hr.  m. 

°C. 

°C. 

p.ct. 

c.c. 

29 

F. 

3,750 

51 

45 

34  .  0-35  .  0 

0.873 

333 

0.970 

83 

M. 

3,100 

51 

1  30 

34.3-35.0 

32.8-35.2 

.669 

481 

.868 

48 

F. 

3,950 

54 

1  30 

33.5-33.8 

-36.0 

.613 

270 

.862 

612 

F. 

4,000 

54 

1  30 

34  .  0-34  .  0 

.989 

399 

.794 

•2 

F. 

3,650 

51 

2   .. 

34.5-35.0 

33.4- 

.909 

422 

1.012 

77 

M. 

3,200 

50 

2   .  . 

32.0-32.0 

.749 

457 

.909 

*In  this  and  the  following  tables  only  the  experimental  conditions  which  might  be  supposed  to 
have  interest  are  quoted.  Therefore,  the  figures  for  the  air  analyses  and  the  percentage 
of  oxygen  in  the  respiration  chamber  are  not  given.  The  latter,  according  to  carbon- 
dioxide  percentage,  would  be  about  20  per  cent. 

•No  food;  during  whole  experiment  very  quiet;  slept  the  latter  half  of  experiment. 

*No  food;  bath,  crying  and  kicking  for  about  a  minute;  otherwise  contented,  sucking  or  half 
asleep;  thin.  » 

4No  food;  quiet,  now  and  then  sucking;  otherwise  without  movements  during  whole  experiment; 
no  crying. 

6No  food;  rather  restless,  hungry;  now  and  then  crying;  see  No.  22,  table  4. 

•No  food;  during  most  of  the  experiment  quiet  and  contented,  now  and  then  sleeping;  cried 
about  one-half  minute;  fat  and  strong. 

7No  food ;  rather  quiet,  now  and  then  kicking  and  trembling  as  if  cold ;  no  crying. 

In  table  2  three  pairs  of  experiments  are  reported,  the  subjects 
being  fairly  well-nourished  infants,  in  all  cases  examined  so  soon  after 
birth  that  the  quotient  still  points  towards  a  predominance  of  carbo- 
hydrate combustion.  Table  2  shows  that  in  all  three  instances  the 
quotient  fell  considerably  in  the  course  of  the  hour  between  the  first 
and  the  second  division  of  the  experiment,  changing  from  a  little  above 
to  a  little  under  0.9. 

I  made  here  the  curious  observation,  which  has  been  partly  expressed 
in  the  remarks  in  the  last  column  of  the  table :  When  a  new-born  fasting 
infant  begins  to  show  signs  of  hunger,  we  can  be  sure  that  its  quotient 
is  lower  than  0.9;  according  to  this  indicating  symptom  the  time  for  the 
beginning  of  the  second  half  of  the  experiment  is  adjusted,  and  hunger 


OBSERVATIONS  BY  HASSELBALCH. 


21 


signs  have  appeared  not  only  in  these  3  experiments,  but  in  about  10 
instances  where  I  have  made  observations  on  the  fasting  new-born 
infant.  The  child7 s  customary  sign  of  hunger,  sucking  its  fingers  or  its 
hand,  can  most  certainly  be  misunderstood,  but  not  by  a  skilled  obser- 
ver. There  is  a  considerable  difference  in  the  playful  manner  in  which 
a  satisfied  and  well-nourished  infant  temporarily  sucks  its  fingers  for 
lack  of  any  other  pastime,  and  the  energy  in  a  hungry  child's  strong 
sucking,  which  is  either  frequently  interrupted  by  angry  crying  or  is 
constant  and  hopeful. 

The  rule  which  is  brought  out  by  table  1,  i.  e.,  that  the  respiratory 
quotient  is  nearer  1.00  the  better  the  condition  of  the  infants,  is  not 
contradicted  by  table  2.  The  child  in  experiments  19  and  20  with  the 
fairly  normal  weight  of  3,600  grams  and  the  unusual  length  of  54  cm. 
had  a  very  marked  birth  swelling  at  the  crown  of  the  head;  its  real 
length  was  barely  over  51  cm.;  and  it  is  inaccurately  recorded  in  the 
remarks  accompanying  the  table  "good  condition." 

Table  2  brings  out  a  second  point:  The  respiratory  quotients  are 
nearer  1  the  sooner  after  birth  the  infant  is  experimented  upon. 

TABLE  2. 


Carbon- 

dioxide 

Experi- 
ment 
No. 

Sex. 

Body- 
weight. 

Height. 

Age. 

Temperature 
of  air  in 
apparatus. 

Body-tempera- 
ture (rectal). 

Carbon 
dioxide 
in  air  of 
cham- 

elimina- 
tion per 
kilogram 
per  hour 

Respir- 
atory 
quo- 

ber. 

at  0°  C. 

tient. 

and  760 

mm. 

gm. 

ra. 

hr.  m. 

°c. 

°C. 

p.  ct. 

c.c. 

218 

}M. 

3,400 

52 

\      30 

1  1  45 

34.3-34.0 
34.5-34.5 

36.2- 
-37.3 

0.678 
.568 

344 
275 

0.933 

.854 

313 

i 

\       45 

34.2-34.8 

36.8- 

1.332 

488 

.921 

414 

>M, 

4,500 

53 

1  1  45 

33.5-33.5 

-37.4 

.775 

300 

.808 

619 
•20 

}M. 

3,600 

54 

f  1  30 
\  2  30 

33.5-33.3 
32.5-32.5 

33.9-35.2 
35.2-35.8 

.605 
.490 

400 
306 

.921 
.849 

:No  food;  no  bath;  wide  awake;  quite  contented;  no  crying. 

2Hungry  and  sleepy  in  last  two- thirds  of  experiment ;  frequently  sleeping,  constantly  awakened; 

no  crying. 

3No  food;  no  bath;  awake  and  contented. 
4Sleeping  quietly  during  nearly  the  whole  experiment. 
6No  food;  bath;  good  condition;  considerable  birth  swelling;  lively  and  contented;  later  hungry 

and  somewhat  sleepy. 
'Stupid;  fell  asleep  now  and  then,  but  awake  most  of  the  time;  cried  1  minute;  at  the  last  lively. 

A  well-nourished  infant,  born  at  full  term,  has  a  store  of  carbohydrate 
which  it  lives  on  either  exclusively  or  largely  in  the  first  hours  of  its 
life;  gradually  this  store  (which  consequently  can  not  be  especially 
large)  is  used  up,  and  this  leads  to  an  increase  in  the  oxidation  of  the 
other  elements. 

In  table  3  five  experiments  are  given  with  4  under-weight,  prema- 
turely-born infants.  The  experiments  indicate  that  such  infants  show 
signs  of  being  very  poorly  nourished,  in  that  their  carbohydrate  store 
is  very  quickly  spent.  But  if  the  infant  is  experimented  upon  soon 


22 


PHYSIOLOGY   OF  THE   NEW-BORN   INFANT. 


enough  after  birth  (as  in  experiments  10  and  11,  in  which  the  infant 
was  placed  in  the  respiration  chamber  immediately  after  tying  the  navel 
cord)  we  see  clearly  that  here  also  we  have  to  deal  with  the  consump- 
tion of  a  store  of  carbohydrate,  which  causes  the  organism  to  burn 
other  materials  in  addition. 

In  experiment  6  the  quotient,  even  within  an  hour  after  birth,  is  0.766. 
Experiment  11  serves  well  for  comparison.  In  this  experiment  an 
infant  of  the  same  length,  but  weighing  200  grams  more,  shows  a  quo- 
tient of  0.897  an  hour  after  birth.  If  experiments  10  and  11  are  com- 
pared, we  find  in  the  case  of  prematurely-born  children,  also,  the  same 
influence  of  condition  of  nutrition  and  of  interval  of  time  after  birth 
upon  the  quotient  as  with  those  born  at  full  term. 

TABLE  3. 


Carbon- 

dioxide 

Experi- 
ment 
No. 

Sex. 

Body- 
weight. 

Height. 

Age. 

Temperature 
of  air  in 
apparatus. 

Body-tempera- 
ture (rectal). 

Carbon 
dioxide 
in  air  of 
cham- 

elimina- 
tion per 
kilogram 
per  hour 

Respir- 
atory 
quo- 

tiont 

ber. 

at  0°  C. 

ulClllr. 

and  760 

mm. 

gm. 

cm. 

hr.  m. 

°C. 

°C. 

p.  ct. 

c.c. 

*6 

M. 

2,550 

47 

I   .. 

33.0-33.5 



0.524 

339 

0.766 

»5 

F. 

1,825 

44 

2   .. 

34.5-34.5 

33.4-35.8 

.392 

273 

.871 

»4 

M. 

2,700 

50 

1  30 

-33 

33.1-35.0 

.729 

464 

.858 

no 

•11 

}M. 

2,750 

47 

d'5 

35.3-35.2 
35  .  2-35  .  1 

36.5- 
-37.8 

.561 
.521 

462 
420 

.912 
.897 

*No  food;  quietly  sleeping  or  sucking  during  the  whole  experiment. 

*No  food;  bath;  sleeping;  respirations  irregular,  very  few  movements;  artificial  delivery;  more 
than  1  month  premature;  died  day  following. 

•No  food;  lively  in  first  half  of  experiment,  sleeping  in  last  half;  born  less  than  1  month  prema- 
turely. 

4No  food;  no  bath;  born  3  weeks  before  time;  crying  about  one-third  of  the  time. 

6Quieter;  crying  about  one-fourth  of  the  time. 

The  infant  in  experiment  5,  although  very  poorly  nourished,  has  a 
somewhat  high  quotient  of  0.871,  2  hours  after  instrumental  delivery. 
The  fact  that  this  child  when  2  hours  old  still  had  a  large  quantity  of 
carbohydrate  to  draw  from  is  presumably  due  to  the  unusually  low 
metabolism.  This  experiment  is  important;  it  is  a  case  of  premature 
interruption  of  pregnancy  of  more  than  a  month  before  the  end  of  the 
full  term.  The  prematurely-born  infant,  therefore,  shows  the  same 
respiratory  quotient  as  the  full-term  child,  indicating  that  it  is  con- 
suming the  remainder  of  its  carbohydrate  supply.  It  is  an  obvious 
supposition  that  during  the  fetal  life  in  mammals,  with  a  physiological 
nourishment  by  the  mother,  there  are  always  sufficient  carbohydrates  at 
hand,  so  that  the  respiratory  exchange  takes  place  normally  with  an  exclu- 
sive metabolism  of  carbohydrates. 

This  supposition  of  mine  is  well  supported  by  literature.  The  fact 
that  the  fetal  tissues  contain  large  quantities  of  glycogen,  which  steadily 
dimmish  during  growth  (always  excepting  the  liver,  in  which  more  and 


OBSERVATIONS   BY   HASSELBALCH.  23 

more  glycogen  is  stored)  ,  and  the  fact  that  the  invertin1  from  the  mucous 
membrane  of  the  small  intestine  provides  the  fetus  with  a  ferment  for 
the  eventual  katabolism  of  this  glycogen,  are  both  arguments  that 
point  towards  the  important  r61e  of  the  carbohydrate  in  the  economy 
of  the  fetus.  Charrin  and  Guillemonat2  find  more  glycogen  in  the  liver 
of  the  pregnant  guinea-pig  than  in  the  non-pregnant;  and  this  is  true 
both  during  inanition  and  during  a  rich  carbohydrate  feeding.  In  preg- 
nant guinea-pigs  this  signifies,  then,  either  an  increased  impulse  towards 
preparing  glycogen  from  its  food  material  or,  in  case  of  need,  from  its 
own  body  elements.  Furthermore,  as  already  mentioned,  Bohr  has 
definitely  shown  that  the  respiratory  quotient  of  the  guinea-pig's 
embryo  is  1.0,  without  reference  to  the  fact  that  the  respiratory  quo- 
tient of  the  mother  may  be  lower.' 

It  may  have  been  noticed  that  in  most  of  the  previous  experiments 
the  percentage  of  carbon  dioxide  in  the  respiration  chamber  was  quite 
high,  most  frequently  between  0.5  and  1.0  per  cent.  This  was  done  in 
order  that  the  unavoidable  errors  in  the  analyses  would  have  less  effect 
upon  the  results.  That  it  is  not  this  fairly  high  percentage  of  carbon 
dioxide  which  has  caused  the  difference  between  my  results  and  those 
of  Scherer  and  Babdk  is  evident  from  the  fact  that  these  scientists  have 
worked  with  approximately  the  same  percentage  of  carbon  dioxide  in 
the  respiration  chamber. 

In  the  double  experiments  in  table  2  the  metabolism,  i.  e.,  the  carbon 
dioxide  per  kilogram  and  per  hour,  in  the  second  half  of  the  experiment 
is  in  every  instance  considerably  less  than  in  the  first  half  of  the  experi- 
ment. This  smaller  metabolism,  which  was  a  result  of  the  infant's 
sleepiness  in  the  later  period,  has  no  modifying  influence  on  the  size 
of  the  quotient.  The  decreasing  lung  ventilation  at  the  beginning  of 
sleep  could  well  be  thought  in  the  first  minutes3  to  be  followed  by  a 
slight  drop  in  the  quotient  (if  the  relationship  in  this  regard  is  the  same 
as  in  adults,  which  is  not  proved),  but  in  the  course  of  the  23  minutes 
of  the  experiment  in  every  case  such  an  effect  was  soon  compensated 
for.  The  experimental  period  is  after  all  so  long  that  we  can  judge 
of  the  nature  of  the  oxidized  material  from  the  quotient  without  fearing 
to  be  misled  by  the  influence  of  lung  ventilation  or  work. 

If  we  wish  to  be  convinced  that  the  quotients  quoted  above  are 
not  affected  systematically  (and  therefore  are  unaffected)  by  work  done 
during  the  experiment  (crying,  kicking,  etc.)  we  need  only  to  compare 
experiments  like  2  and  9  in  table  1  on  the  one  hand  and  3  and  8  in  table 
1,  and  5  in  table  3,  on  the  other.  The  comparison  between  3  and  8  is 
especially  convincing;  in  3  there  is  twice  as  great  a  metabolism  as  in  8, 
due  to  the  difference  in  muscular  activity,  but  the  same  quotient  is 
found  with  both. 

That  the  percentage  of  carbon  dioxide  in  the  atmosphere  about  the 
infant  can  not  be  considered  to  have  an  effect  upon  the  quotient  has 
already  been  quite  definitely  settled  for  adults  by  Speck's4  experiments. 
In  his  experiments  the  same  percentage  of  carbon  dioxide  as  that  used 


,  Zeitschr.  f.  Biol.,  1895,  32. 
2Charrin  and  Guillemonat,  Compt.  rend,  de  la  HOC.  de  biol.,  1900. 
3Speck,  Physiologic  des  menschlichen  Athmens,  Leipsic,  1892,  p.  16.         4Speck,  loc.  cit.,  p.  133. 


24  PHYSIOLOGY   OF   THE   NEW-BORN   INFANT. 

in  these  experiments  is  shown  to  bring  about  a  decrease  in  the  oxygen 
intake,  and  a  consequent  increase  in  the  respiratory  quotient,  only 
when  the  oxygen  percentage  in  the  atmosphere  is  at  the  same  time 
very  low  (i.  e.,  8  per  cent  against  20  per  cent  in  my  experiments).  This 
fact  is  strikingly  demonstrated  by  a  comparison  of  12  and  2  in  table  1 
(with  the  same  percentage  of  carbon  dioxide  and  extreme  difference 
between  quotients)  and  a  comparison  of  13  in  table  2  and  5  in  table  3 
(with  an  extreme  difference  between  the  percentage  of  carbon  dioxide 
and  approximately  the  same  quotient). 

As  regards  the  amount  of  the  metabolism  in  the  above  experiments  it 
seems  impossible  for  me  to  conclude  anything  else  from  the  tables  than 
that  the  activity  of  the  infant  is  the  chief  determining  factor,  and  that 
the  influence  of  other  conditions,  such  as  the  condition  of  nourishment, 
age,  etc.,  is  not  demonstrated,  at  least  by  my  method  of  experimenta- 
tion. The  influence  of  activity  is  overwhelming  and  is  observed 
regularly  in  the  double  experiments  in  table  2,  and  10  and  11  in  table  3, 
in  which  the  child  in  the  second  experiment  is  always  either  drowsy  or 
asleep.  In  the  single  experiments,  also,  we  find  a  striking  parallelism 
between  the  amount  of  the  metabolism  recorded  and  the  intensity  of 
the  activity.  It  is  naturally  quite  difficult  to  judge  of  and  to  express 
in  words  the  degree  of  strength  with  which  the  infant  has  contracted 
its  muscles  in  the  course  of  23  minutes.  In  the  experimental  pairs  17- 
18  and  19-20  (table  2)  I  have  repeatedly  awakened  the  infants  in  the 
second  experiment  by  rapping  loudly  on  the  cover  of  the  respiration 
chamber.  The  purpose  was  to  keep  the  activity  and  thereby  the 
metabolism  artificially  at  the  same  level  as  in  the  first  experiment. 
Although  the  infants  reacted  to  every  rap  with  severe  general  contrac- 
tion of  the  muscles,  the  drowsiness  throughout  the  entire  period  has 
been  the  determining  factor;  the  metabolism  in  experiments  19  and  20 
fell  25  per  cent. 

Even  though  it  is  difficult  to  determine  the  work  which  the  different 
children  have  done  during  the  experiment  and  therefore  difficult  to 
arrive  at  a  numerical  expression  for  the  effect  of  work  on  the  amount 
of  the  metabolism,  it  is  easy  to  convince  one's  self  of  the  absolute 
absence  of  visible  contractions.  When  such  a  condition  has  prevailed 
throughout  the  23  minutes  of  the  experiment  we  find  a  very  low  metabo- 
lism value — from  270  to  300  c.c.  carbon  dioxide  per  kilogram  and  per 
hour.  Such  figures  are  found  both  for  infants  overweight  (3,950  grams  in 
experiment  8  of  table  1,  etc.)  and  for  infants  underweight  (1,825  grams  in 
experiment  5  of  table  3,  etc.).  After  due  reflection  this  is  not  surprising. 
The  heat  regulation  of  a  new-born  infant1  is  very  poorly  developed. 
Even  if  it  were  not  poorly  developed,  the  temperature  during  the 
experiment  is  so  regulated  that  the  question  of  the  feeble  heat  regula- 
tion of  the  child  is  eliminated  as  far  as  possible.  Thus  every  experi- 
mental condition  which  would  produce  a  smaller  metabolism  per  unit 
of  weight  in  the  large  infant  with  a  relatively  small  surface  than  in 
the  smaller  infant  with  a  relatively  large  surface  is  eliminated.  But 
there  is  cause  for  reflection  in  the  fact  that  a  figure  like  270  c.c.  for  the 

'Babdk,  Archiv  f.  d.  ges.  Physiol.,  1902,  89,  p.  154. 


OBSERVATIONS   BY   HASSELBALCH.  25 

carbon  dioxide  per  kilogram  and  per  hour  for  a  new-born  infant  is  not 
essentially  higher  than  the  corresponding  figure  for  a  grown  individual 
in  absolute  repose. 

There  is  reason  to  investigate  whether  the  different  temperatures  of 
the  children  experimented  upon  have  had  an  effect  upon  the  difference 
in  the  amount  of  the  metabolism.  As  previously  mentioned,  a  fairly 
accurate  value  for  the  infant's  temperature  during  the  experiment  is 
the  last  figure  in  the  column  headed  "  Body-temperature"  in  the  tables. 
Recorded  in  this  way,  the  infants'  body-temperatures  during  the  experi- 
ments do  not  show  large  differences,  and  these  are  in  all  instances 
plainly  not  parallel  with  the  differences  in  the  amount  of  the  metabo- 
lism; I  emphasize  experiment  3,  table  1  (temp.  35.2°,  metabolism  481), 
in  comparison  with  experiment  8-,  table  1  (36.0°,  270) ;  experiment  5, 
table  3  (35.8°,  273)  with  experiment  4,  table  3  (35.0°,  464),  etc.  More- 
over, it  is  sufficiently  well  known  that  strong  and  continuous  crying  can 
raise  an  infant's  temperature  about  0.5°.  As  crying  is  followed  by  a 
rise  in  metabolism,  a  certain  degree  of  parallelism  between  the  infant's 
temperature  and  the  figure  for  the  metabolism  was  expected. 

As  regards  the  low  temperatures  after  the  birth-bath,  they  are  for 
full-term  and  strong  infants  obviously  considerably  lower  than  is 
considered  the  rule.  Vierordt1  reports  a  temperature  fall  on  account 
of  birth  and  birth-bath  at  an  average  of  1°  C;  a  fall  of  1.7°  C.  " comes 
very  rarely,"  but  with  delicate  infants  it  may  amount  to  even  4.7°  C. 

In  my  experiments  the  normal  children  in  experiments  3  and  2  in 
table  1  show  in  one-half  hour  and  2  hours  after  birth  a  temperature 
which  is  4°  C.  or  more  below  normal.  When  no  bath  after  birth  was 
given  prior  to  the  experiment,  the  cooling-off  after  birth  has  been  fol- 
lowed by  a  fall  in  temperature  of  about  1°  C.  (experiments  17  and  13  in 
table  2  and  experiment  10  in  table  3).  I  would  not  dispute  the  fact 
that  the  tepid  birth-bath  is  in  all  cases  a  very  important  means  of 
reflexly  starting  the  respirations,  but  I  consider  it  very  possible  that 
the  cooling  off  brought  about  by  the  bath  can  be  carried  too  far,  and  if 
special  arrangements  have  not  been  made  for  effectively  warming  the 
child  after  the  bath,  the  cooling  effect  can  be  of  too  long  duration. 

How  is  the  respiratory  metabolism  of  the  new-born  infant  altered 
under  the  influence  of  food,  as  well  with  respect  to  the  quotient  as  to 
the  amount  of  the  metabolism?  When  a  hungry  individual  is  put 
on  a  nearly  exclusive  carbohydrate  diet,2  his  respiratory  quotient 
reaches  1  about  an  hour  after  the  first  meal.  In  the  course  of  an  hour, 
therefore,  the  absorption  and  combustion  of  the  carbohydrates  in  the 
different  organs  is  in  full  operation.  If  we  make  an  experiment  similar 
to  this  with  fat,  the  quotient  shows  that  the  time  for  the  combustion 
of  fat  is  considerably  longer,  i.  e.,  about  3  hours  after  eating;  something 
similar  is  true  of  proteids.  Carbohydrates,  therefore,  are  for  grown 
individuals  the  food  element  most  easily  and  most  quickly  consumed. 
This  agrees  very  well  with  the  fact  that  Mosso  found  with  dogs  an 
increase  in  temperature  of  about  1°  C.  an  hour  after  taking  1  to  2  grams 

lVierordt,  Physiol.  d.  Kindesalters,  1877,  pp.  152-154. 

2Speck,  Physiologic des  menschlichen  Athmens,  Leipsic,  1892,  p.  35;  Magnus-Levy,  Archiv  f.  d. 
ges.  Physiol.,  1894,  55,  p.  1. 


26 


PHYSIOLOGY   OF   THE    NEW-BORN   INFANT. 


of  cane  sugar  per  kilogram  of  the  dog's  body-weight.  From  the  records 
of  the  body-temperature  of  the  dog  during  and  after  a  meal,  consisting 
of  cane  sugar  or  of  isodynamic  quantities  of  bread,  Mosso  concludes 
that  about  an  hour  after  taking  the  sugar  is  all  absorbed,  small  quanti- 
ties being  used  entirely  for  the  formation  of  heat  and  larger  deposits 
being  used  in  part  for  the  same  purpose  and  in  part  stored  for  future 
consumption.  Bread  is  utilized  in  the  same  way,  but  more  slowly, 
since  it  takes  longer  before  the  other  food  elements  in  the  bread  are 
oxidized.  The  bread  as  a  whole,  therefore,  can  not  develop  a  heat 
influence  so  suddenly  as  can  isodynamic  quantities  of  sugar. 

TABLE  4. 


Carbon- 

dioxide 

Experi- 
ment 
No. 

Sex. 

Body- 
weight. 

Height. 

Age. 

Temperature 
of  air  in 
apparatus. 

Body-tempera- 
ture (rectal). 

Carbon 
dioxide 
in  air  of 
cham- 

elimina- 
tion per 
kilogram 
per  hour 

Respir- 
atory 
quo- 

tipnt 

ber. 

at  0°  C. 

tieiiu. 

and  760 

mm. 

Q7ft>* 

cm. 

d.hr. 

°C. 

°C. 

p.ct. 

c.c. 

125 

M. 

3,600 

5   .. 

33.0-33.0 

36.5-37.0 

1.148 

510 

0.930 

222 

F. 

4,100 

54 

5   .. 

31     -31 

36.0-36.8 

1.133 

487 

.916 

321 

M. 

3,250 

52 

2   .  . 

32.0-32.0 

35.2-36.8 

.851 

478 

.799 

<24 

M. 

3,400 

52 

5   .  . 

32.3-32.7 

35.4-36.6 

.743 

395 

.807 

615 
16 

}». 

1,900 

5   .. 

J33.5-33.8 
\33.4-33.7 

.260 
.373 

205 
235 

.770 
.806 

«28 

M. 

3,000 

50 

..    15 

32.5-32.5 

37.0-37.0 

.707 

482 

.849 

730 

F. 

2,950 

1    .  . 

31.8-32.5 

36.8-37.0 

.894 

642 

.872 

«23 

F. 

2,550 

.  .   15 

32.0-32.0 

34.4-34.6 

.449 

283 

.691 

breast-fed  1  hour  before  experiment;  cried  somewhat  for  about  8  minutes;  passage  of  urine  and 
feces;  during  the  last  5  minutes  asleep.  See  experiment  27,  table  5. 

2Breast-fed;  same  as  subject  in  experiment  12,  table  1;  breast-fed  1  hour  previously;  awake  and 
satisfied. 

•Same  as  subject  in  17  and  18  in  table  2;  slight  jaundice;  breast-fed  2  hours  previous  to  experi- 
ment; cried  3  minutes;  awake  and  lively,  sucking  its  fingers. 

4Breast-fed  2  hours  and  again  just  before  experiment;  asleep  or  drowsy;  only  a  few  movements; 
no  signs  of  hunger. 

•Incubator  infant;  weighed  at  birth  1,950  grams;  takes  to  the  breast  poorly;  is  put  to  the  breast 
every  2  hours;  last  time  just  previous  to  experiment;  fast  asleep.  This  applies  to 
experiment  16  as  well. 

•Bottle  and  breast;  last  meal  3  hours  and  again  just  previous  to  experiment;  awake  and  lively. 
See  experiment  29,  table  5. 

'Breast;  last  meal  3  hours  and  again  just  before  experiment;  violently  crying  more  than  two- 
thirds  of  the  time;  rest  of  the  time  in  light  sleep.  See  experiment  31,  table  5. 

8Breast;  born  2  to  3  weeks  prematurely;  breast-fed  altogether  2  times,  5  hours  before  and  again 
just  before  experiment;  took  to  breast  well;  absolutely  quiet,  half  and  wholly  asleep. 

An  individual  on  a  liberal  mixed  diet  does  not  show  variations  in  the 
respiratory  quotient  which  would  suggest  a  selective  choice  of  the 
different  foodstuffs.  For  instance,  he  does  not  have  an  hour  after  a 
meal  a  respiratory  quotient  of  1 ,  2  hours  after  a  quotient  of  0.8,  and  3 
hours  after  0.7,  but  would,  at  any  time  selected,  have  a  quotient  which 
varies  but  little  from  0.88,  for  example.  The  reason  for  this  is  that  the 
nourishment  is  plentiful,  or,  in  other  words,  that  there  is  in  the  circu- 
lation almost  the  same  mixture  of  all  three  chief  nutrients  or  their 


OBSERVATIONS   BY   HASSELBALCH.  27 

intermediate  metabolism  products.  Meals,  which  as  a  rule  follow  so 
quickly  after  each  other  that  the  fat  and  albumin  absorption  in  the 
course  of  a  day  does  not  cease  at  all,  can  therefore  not  have  any  recog- 
nizable influence  on  the  quotient.  The  evident  conclusion  is  that  if 
a  meal  (having  constant  composition)  causes  variations  in  the  quotient 
of  the  above-mentioned  character,  it  must  mean  that  the  nourishment 
is  insufficient.  I  am  not  certain  whether  experiments  favor  this  con- 
clusion, but  I  do  not  doubt  that  the  supposition  is  true  in  the  case  of 
the  adult. 

The  meal  affects  the  amount  of  the  metabolism  in  such  a  way  that 
the  activity  of  the  muscles  and  of  the  glands,  caused  by  the  ingestion  of 
the  food,  increases  the  respiratory  metabolism  about  10  per  cent. 
If  we  consider  table  4,  in  which  the  experiments  are  arranged  according 
to  the  time  which  has  elapsed  after  the  last  meal,  there  seems  to  be 
little  doubt  concerning  the  effect  of  the  meal  on  the  respiratory  quo- 
tient. In  the  two  experiments  (25  and  22)  which  began  an  hour  after 
the  meal,  the  middle  of  the  experiment  corresponding  to  1 J  hours  after 
the  meal  (intervals  which  are  important  in  carbohydrate  metabolism), 
high  quotients  are  found,  namely,  0.930  and  0.916.  These  quotients 
point  towards  a  predominant  carbohydrate  metabolism.  In  experi- 
ment 21  the  meal  was  given  2  hours  previous  and  the  quotient  is  0.799. 
Almost  the  same  quotient  was  found  in  experiment  24  (0.807).  Pre- 
vious to  this  experiment  the  child  had  not  been  fed  for  2  hours,  but  was 
put  to  the  breast  just  before  the  experiment  began.  The  preceding 
meal  may,  therefore,  be  considered  as  having  increased  the  metabolism 
but  not  as  having  changed  the  quotient,  because  at  the  end  of  the  exper- 
iment only  38  minutes  had  elapsed  since  the  meal  (15  plus  23  minutes). 
The  metabolism  during  the  experiment  was  the  metabolism  of  the  ele- 
ments from  the  previous  meal.  The  exact  correspondence  between 
the  quotients  in  these  two  experiments  also  seems  to  indicate  that 
the  metabolism  of  the  food  given  just  before  experiment  24  did  not 
begin  during  the  experimental  period. 

Experiments  15  and  16,  with  a  5-day-old  incubator  child  for  subject, 
are  interesting  because  they  point  towards  the  time  when  the  metabo- 
lism of  a  meal  begins;  they  were  conducted  at  1-hour  intervals.  The 
child  received  its  last  meal  2  hours  before  experiment  15,  and  therefore 
in  this  experiment  has  a  quotient  of  0.770  (approximately  the  same  as 
the  quotient  in  21  and  24).  With  experiment  16,  however,  the  child 
had  its  last  meal  an  hour  previous  to  the  beginning  of  the  experimental 
period;  we  therefore  find  an  increased  quotient,  i.  e.,  0.806. 

In  experiments  28  and  30,  both  with  infants  fed  at  the  breast  3  hours 
previous  to  and  again  just  before  the  experiment,  quotients  of  0.849 
and  0.872  were  obtained,  which  again  show  fair  uniformity.  These 
quotients  are  considerably  lower  than  those  obtained  one-half  hour 
after  the  meal,  but  higher  than  those  obtained  2  to  2|  hours  after. 
This  may  be  only  accidental,  but  it  is  impossible  to  decide  concerning 
this  point.  If  we  determine  the  metabolism  5  hours  after  the  meal, 
as  in  experimejit  23,  the  quotient  is  found  to  be  0.691,  indicating  the 
katabolism  of  fat. 


28  PHYSIOLOGY   OF   THE   NEW-BORN   INFANT. 

It  is  quite  clear  to  me  that  in  investigating  these  circumstances  it 
would  have  been  experimentally  more  correct  to  have  used  the  same 
instead  of  different  infants.  The  material  for  the  investigations,  how- 
ever, was  collected  for  another  purpose.  Nevertheless  the  dependence 
of  the  respiratory  quotient  upon  the  interval  of  time  elapsing  after 
the  last  meal  is  shown  in  table  4,  and  in  such  a  striking  manner  that 
there  can  hardly  be  any  other  interpretation. 

There  is,  however,  no  doubt  about  one  point.  Even  though  the 
composition  of  the  food  of  the  infant  is  much  more  constant  than  that 
of  the  adult,  the  respiratory  quotient  of  the  infant  varies  continually 
with  the  meals,  so  that  it  is  highest  about  If  hours  afterwards  (during 
this  period  the  metabolism  of  lactose  is  chiefly  going  on) ,  and  very  low 
about  5  hours  after,  when  the  lactose  from  the  last  meal  had  been 
used  up.  I  would  not  insist  that  this  is  definitely  in  favor  of  more 
frequent  feeding  than  the  ordinary  5  feedings  during  the  course  of  the 
day,  but  it  certainly  deserves  some  consideration. 

On  the  other  hand,  it  is  possible  that  it  might  be  harmful  to  the  infant 
if  the  meals  were  so  near  together  that  the  respiratory  quotient  remained 
constant  throughout  the  day.  In  any  case  the  problem  is  interesting 
and  deserves  a  more  thorough  investigation,  especially  in  the  case  of  the 
same  child  throughout  a  rather  long  interval  of  time,  with  varying 
frequency  of  feeding  with  the  same  quantity  of  food  and  under  constant 
control  of  the  weight  curve. 

Table  4  does  not  give  any  new  information  concerning  the  amount 
of  the  metabolism.  The  influence  of  activity  is  also  quite  apparent 
here.  The  premature  incubator  infant  in  experiments  15  and  16, 
which  was  practically  motionless  during  the  experiments,  has  a  metabo- 
lism even  lower  than  that  found  in  the  experiments  with  infants 
immediately  after  birth;  it  is  interesting  to  note  that  the  metabolism 
rises  in  the  second  experiment  (both  the  carbon  dioxide  produced  and 
the  oxygen  consumed),  because  this  is  supposedly  to  be  interpreted  in 
the  same  manner  as  the  rise  of  the  quotient  in  experiment  16.  The 
work  of  digestion  is  greater  hi  experiment  16  than  in  experiment  15. 
At  any  rate,  it  was  impossible  to  recognize  a  difference  in  the  muscular 
activity  of  the  infant  in  the  two  experiments,  as  the  child  was  lying 
relaxed  and  asleep.  The  quotients  for  the  infants  spoken  of  as  "  lively 
and  content"  are  somewhat  higher  than  those  of  similar  cases  in  tables 
1,  2,  and  3;  but  it  is  also  striking  how  much  more  energy  is  displayed 
by  the  child  a  few  days  old  than  by  the  new-born  infant,  exhausted 
after  birth. 

In  experiment  30  we  find  an  enormous  metabolism,  642  c.c.  of  carbon 
dioxide  per  kilogram  and  per  hour;  but  in  this  case  we  observe  that  the 
child  was  "  violently  crying  more  than  two-thirds  of  the  time."  Evi- 
dently we  can  not  overestimate  the  increased  metabolism  due  to  the 
incessant  crying  of  feeble  infants. 

Experiment  27  (not  given  in  the  tables)  illustrates  the  effect  of  crying 
on  the  amount  of  the  metabolism.  By  moderately  lowering  the  tem- 
perature (which  caused  a  drop  in  the  body-temperature  of  0.4°  C.)  we 
succeeded  in  making  the  child  cry  very  violently  for  about  17  min- 


OBSERVATIONS   BY   HASSELBALCH.  29 

utes.  The  experiment  was  made  with  the  same  male  infant  as  experi- 
ment 25  in  table  4,  the  weight  of  the  child  being  3,600  grams  and  the 
age  6  days.  It  was  breast-fed.  The  temperature  of  the  apparatus 
was  25°  to  26°  C.;  the  body-temperature  of  the  infant  was  37.0°  to 
36.6°  C.  The  percentage  of  carbon  dioxide  in  the  air  of  the  chamber 
was  1.534;  the  carbon-dioxide  elimination  per  kilogram  per  hour, 
reduced  to  0°  C.  and  760  mm.,  was  764  c.c.  and  the  respiratory  quotient 
0.897.  The  child  was  crying  violently  three-quarters  of  the  experi- 
mental period  and  was  evidently  cold.  In  the  middle  of  the  experi- 
ment there  was  a  quiet  period  with  a  little  sobbing.  It  would  be 
erroneous  to  consider  the  great  increase  in  metabolism  (compare 
experiment  25,  table  4)  in  this  experiment  a  result  of  the  child's 
"  chemical  heat  regulation"  brought  about  by  a  cold  reflex.1  The 
infant  would  have  reacted  to  any  other  equally  powerful  irritant  with  as 
severe  crying  and  with  equally  high  metabolism. 

Even  if  the  previous  experiments  leave  no  doubt  that  the  carbo- 
hydrates of  the  food  play  the  same  r61e  in  the  infant's  nutrition  as  in 
that  of  adults,  namely,  that  of  the  most  accessible  food  elements  and 
consequently  most  quickly  consumed  for  heat  production,  and  even  if 
the  results  in  table  4  are  most  easily  interpreted  on  the  supposition 
that  the  absorption  and  metabolism  of  carbohydrates  reach  their 
climax  1  to  If  hours  after  the  meal,  further  experimental  evidence  is 
still  needed  of  the  correctness  of  this  hypothesis.  With  this  purpose 
in  mind  three  infants  were  put  on  a  diet  so  arranged  that  meats  were 
given  between  their  regular  feedings.  These  meals  consisted  of  4  to  5 
grams  of  grape  or  milk  sugar  dissolved  in  a  little  water. 

In  experiment  29  of  table  5  the  respiration  experiment  commences  3 
hours  after  the  milk  meal  and  about  If  hours  after  the  lactose  meal. 
The  quotient  is  1.0.  In  experiment  26,  in  which  the  grape-sugar  was 
given  4  hours  and  again  one-half  hour  previous  to  the  experiment 
(breast-feeding  between  the  two  feedings  about  2  hours  previous  to  the 
experiment),  it  is  seen  that  the  quotient  0.869  does  not  point  towards 
an  exclusive  carbohydrate  metabolism.  In  the  course  of  the  half 
hour  the  absorption  of  the  administered  grape-sugar  has  not  taken  place. 
Finally,  in  experiment  31,  undertaken  about  3f  hours  after  the  last 
milk  meal  and  about  2f  hours  after  the  last  grape-sugar  feeding,  the 
quotient  is  0.845,  an  index  that  the  metabolism  of  the  4  grams  of  grape- 
sugar  has  to  a  great  extent  taken  place  as  quickly  as  2\  hours  after  admin- 
istration. 

This  result  corresponds  strikingly  with  those  obtained  by  Speck  and 
Magnus-Levy  with  adults  (my  discussion  of  the  results  in  table  4  were 
based  on  the  results  obtained  by  these  two  authors),  and  with  Mosso's 
demonstration  of  a  temperature  rise  of  1°  C.  in  the  case  of  a  starving 
dog,  about  an  hour  after  the  ingestion  of  an  amount  of  sugar  correspond- 
ing to  that  used  in  these  experiments.  It  is  thus  clear  that  the  custom 
of  feeding  sugar-water  immediately  after  the  birth-bath  rests  upon  a 


(Archiv  f.  d.  ges.  PhysioL,  1902,  89,  p.  166)  interprets  a  rise  in  metabolism  from  332 
c.c.  to  579  c.c.  carbon  dioxide  as  a  sign  of  an  "auffallige  Thatigkeit  der  chemischen  Regulation," 
without  giving  information  about  the  child's  behavior  in  the  two  cases. 


30 


PHYSIOLOGY   OF  THE   NEW-BORN   INFANT. 


very  sound  principle.  Of  all  the  elements  of  nutrition  sugar  is  digested 
by  the  infant  the  most  quickly  and  the  most  easily,  and  doubtless 
causes  a  rise  in  temperature  very  much  to  be  desired,  because  of  the 
cooling-off  at  birth  and  during  the  birth-bath. 

Experiment  1  of  table  5  is  an  experiment  which  should  illustrate 
this  utilization  of  sugar,  but  there  are  some  objections.  In  the  first 
place,  it  was  not  wise  to  select  a  period  3  hours  after  birth  for  feeding 
with  sugar;  in  the  second  place,  it  will  always  be  difficult  to  demonstrate 
in  respiration  experiments  the  utilization  of  sugar  at  such  a  period,  for 
even  without  sugar  the  quotient  at  this  period  is  close  to  1.0.  But  a 
direct  demonstration  of  this  point  is  unnecessary.  The  fact  that  the 
small  intestine  of  the  fetus  contains  invertin  shows  that  it  is  equipped 
for  the  digestion  of  carbohydrates,  and  therefore  favors  the  supposition 
that  the  new-born  infant  should  be  able  to  digest  cane-sugar  without 
difficulty  immediately  after  birth. 

TABLE  5. 


Carbon- 

dioxide 

Experi- 
ment 
No. 

Sex. 

Body- 
weight. 

Height. 

Age. 

Temperature 
of  air  in 
apparatus. 

Body-tempera- 
ture (rectal). 

Carbon 
dioxide 
in  air  of 
cham- 

elimina- 
tion per 
kilogram 
per  hour 

Respir- 
atory 
quo- 

4  iri»i  + 

ber. 

at  0°  C. 

nent. 

and  760 

mm. 

QW:. 

cm. 

d.  hr. 

°C. 

°C. 

p.  ct. 

c.c. 

12Q 

M. 

2,950 

50 

2   .. 

31.8-32.1 

36.4-36.5 

0.806 

617 

1.027 

*26 

F. 

2,450 

2   .  . 

31.8-32.1 

36.0-35.7 

.553 

370 

.869 

'31 

F. 

2,950 

2   .. 

31.0-31.3 

36.3-36.7 

.511 

343 

.845 

<1 

F. 

3,700 

51 

..     3 

33.5-35.0 

34.2-35.4 

1.291 

500 

.902 

1  Bottle  and  breast;  same  as  subject  of  experiment  28  in  table  4;  in  last  24  hours  between  the 

meal- times  fed  with  5x4  grams  milk-sugar,  last  time  l£  hours  before  experiment.    Crying 

violently  for  4  minutes,  afterwards  half  or  wholly  asleep. 
2Breast;  same  as  subject  of  experiment  23  in  table  4;  in  last  36  hours  5x5  grams  grape-sugar, 

last  4  hours  and  £  hour  before  experiment;  sleeping  or  dozing;  now  and  then  vigorous 

movements. 
Breast;  same  as  subject  of  experiment  30  in  table  4;  in  the  last  24  hours  5x4  grams  grape-sugar; 

last  feeding  2\  hours  before  experiment;  half  or  wholly  asleep. 
4Sugar-water  at  birth;  bath;  crying  about  one-half  of  the  time;  otherwise  restless,  kicking,  and 

perspiring. 

It  would  be  unreasonable  to  dispute  the  fact  that  mother's  milk  is 
the  ideal  nourishment  for  the  infant.  It  is  well  to  note,  however,  that 
the  infant  must  be  born  at  full  term  and  be  healthy.  With  premature 
infants  and  infants  with  intestinal  catarrh  or  other  digestive  ailments, 
which  result  in  diarrhea  and  rapid  loss  of  weight,  it  is  quite  a  different 
matter. 

Recent  investigators  in  this  line  tend  more  towards  localizing  the 
logical  cause  of  digestive  diseases  in  those  organs  in  which  the  final 
katabolism  of  the  food  elements  takes  place,  instead  of  in  the  mucous 
membrane  of  the  digestive  tract  and  the  accessory  digestive  glands; 
indeed,  there  are  many  points  which  favor  a  pathological  retarded 
development  of  the  oxidative  functions  of  the  liver  tissues. 


OBSERVATIONS   BY   HASSELBALCH.  31 

Meinhard  Pfaundler1  has  shown  in  an  interesting  paper  that  an 
infant,  and  especially  an  infant  weakened  from  some  illness,  is  unable  to 
oxidize  the  fat  and  albumin  in  the  nourishment  as  completely  as  the  adult, 
and  he  has  shown  by  experiments  that  this  is  due  to  some  extent 
to  the  small  oxidative  power  of  the  liver  tissue. 

Carbohydrates  receive  a  prominent  place  as  that  constituent  in  milk 
which  is  most  easily  and  most  completely  oxidized  under  all  conditions, 
and  which  is  therefore  an  important  element  in  the  feeding  of  the 
infant,  whose  fat  and  albumin  digestion  is  supposedly  overworked. 
In  such  cases  the  mother's  milk  is  not  the  ideal  food,  for  its  contents  of 
fat  and  albumin  (which  can  not  be  digested  and  whose  products  of 
decomposition  may  do  harm  in  the  intestine)  are  altogether  too  large 
and  cause  the  child  in  reality  to  starve. 

In  reviewing  the  extensive  amount  of  literature  on  artificial  feeding 
of  atrophic  infants,  it  is  evident  that  the  composition  which  has  had 
the  best  results,  Keller's  malt  soup  (a  modified  Liebig  soup),  points 
towards  feeding  largely  with  easily  digested  carbohydrates  (maltose). 
With  this  kind  of  feeding  the  formerly  atonic  and  poorly-nourished 
infant  thrives  and  the  disease  is,  as  a  rule,  cured  at  one  stroke.  If, 
therefore,  it  is  demonstrated  that  mother's  milk  is  not  the  most  favor- 
able nourishment  in  all  pathological  cases,  it  is  well,  bearing  the  previ- 
ous results  in  mind,  not  to  take  it  for  granted  that  mother's  milk  is 
indicated  in  the  case  of  the  premature  infant,  but  to  consider  whether 
feeding  with  relatively  large  amounts  of  carbohydrates  would  not  be 
preferable. 

CONCLUSIONS. 

I.  The  well-nourished  infant,  born  at  full  term,  has  a  store  of  carbo- 
hydrates (glycogen)  in  its  organs,  which  is  spent  in  the  course 
of  a  few  hours. 

II.  The  metabolism  of  a  poorly-nourished  and  premature  infant 
depends  chiefly  on  the  oxidation  of  carbohydrates  during  the 
first  hours  of  life. 

III.  There  is  every  reason  to  suppose  that  the  metabolism  of  the 

normal,  well-nourished  human  fetus  consists  of  the  oxidation 
of  carbohydrates. 

IV.  When  the  infant  is  fed  with  mother's  milk,  the  respiratory  metab- 

olism shows  a  mixed  quotient,  which  varies  with  the  meals 
in  such  a  way  as  to  indicate  that  milk  sugar  is  the  element 
most  quickly  burned,  that  is,  about  1£  hours  after  the  meal. 
This  fact  is  confirmed  by  experiments. 

V.  The  amount  of  the  infant's  metabolism  is  to  a  very  large  extent 
dependent  upon  muscular  contractions.  At  32°  C.  and  with 
least  possible  work,  the  metabolism  per  kilogram  is  hardly 
greater  than  that  of  the  adult  at  absolute  rest. 

VI.  The  relative  ease  with  which  carbohydrates  are  digested  favors 
their  extensive  use  in  cases  where  the  ability  to  digest  the 
other  constituents  of  human  milk  is  decreased. 

Meinhard  Pfaundler,  Jahrb.  f.  Kinderheilk.,  1901, 54,  p.  247.     See  also  here  a  large  amount  of 
literature  on  the  subject. 


32  PHYSIOLOGY   OF   THE    NEW-BORN   INFANT. 

DISCUSSION  OF  HASSELBALCH'S  RESEARCH. 

We  consider  it  peculiarly  unfortunate  that  in  our  two  earlier  publica- 
tions reference  to  Hasselbalch's  research  and  to  his  striking  conclusions 
was  inadvertently  omitted,  and  although  at  that  time  we  were  unable 
to  comment  intelligently  upon  the  results  or  make  a  satisfactory 
abstract  of  them,  since  there  were  some  difficulties  in  the  translation, 
nevertheless  it  would  have  been  desirable  to  call  attention  earlier  to 
the  existence  of  this  wholly  remarkable  piece  of  research  upon  infant 
metabolism.  Although  the  study  was  made  11  years  ago,  the  same 
degree  of  care  and  nicety  of  technique  which  has  characterized  Hassel- 
balch's subsequent  observations  is  apparent  in  this  research.  It  is 
obvious  that  we  have  here  for  the  first  time  quantitative  measurements 
of  the  gaseous  metabolism  of  infants  by  a  study  of  the  carbon-dioxide 
increment  and  oxygen  deficit  in  the  ventilating  current  of  air.  It  is  an 
interesting  fact,  which  should  certainly  be  pointed  out,  that  the  appa- 
ratus used  by  Hasselbalch  for  this  study  embodied  the  same  principle 
as  the  Jaquet1  apparatus,  and,  indeed,  both  forms  of  apparatus  were 
described  in  the  same  year,  thus  proving  independent  simultaneous 
development. 

Of  particular  importance  in  studying  the  respiratory  exchange  is  a 
special  appreciation  of  the  significance  of  the  difficulties  of  determining 
the  oxygen  in  any  gaseous  mixture,  even  in  ordinary  atmospheric  air. 
Researches  in  the  Nutrition  Laboratory  have  shown  that  the  external 
air  is  of  absolutely  constant  composition,  irrespective  of  seasons,  wind 
direction,  weather  conditions,  barometric  pressure,  and  altitude.2 
Consequently  it  can  be  assumed  that  any  gas-analysis  apparatus  which 
fails  to  give  constant  values  for  the  oxygen  content  of  the  atmospheric 
air  may  be  considered  on  this  a  priori  evidence  as  being  an  inaccurate 
apparatus,  or  the  technique  is  at  fault. 

It  is,  furthermore,  obvious  that  the  greater  the  carbon-dioxide  incre- 
ment and  the  greater  the  oxygen  deficit  in  the  ventilating  current  of  air, 
the  less  the  analytical  errors  will  influence  the  calculation  of  the  respira- 
tory quotient.  It  has  been  frequently  pointed  out  that  those  using 
the  Jaquet  method  are  too  often  inclined  so  to  adjust  the  ventilating 
air-current  as  to  have  a  minimum  carbon-dioxide  increase  and  an 
equivalent  oxygen  deficit.  When  this  carbon-dioxide  increment  is 
less  than  0.5  per  cent,  analytical  errors  play  a  great  r61e  not  only  in  the 
calculation  of  the  respiratory  quotient,  but  likewise  to  a  certain  extent 
in  the  calculation  of  the  total  metabolism.  Since  the  analytical  errors 
in  the  determination  of  the  carbon  dioxide  are  very  much  less  than  those 
in  determining  oxygen,  this  may  not  of  necessity  be  a  serious  matter. 
On  the  other  hand,  the  exact  determination  of  oxygen  necessitates  the 
skill  of  the  best  trained  analyst  and  an  especially  accurate  gas-analysis 
apparatus  with  a  carefully  controlled  technique.  When  the  oxygen 

1  Jaquet,  Verhandl.  d.  Naturforsch.  Gesellsch.  in  Basel,  1904,  15,  p.  252. 
Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  166,  1912. 


EARLIER   RESEARCHES  WITH   NEW-BORN   INFANTS.  33 

deficit  is  less  than  0.7  per  cent,  analytical  errors  of  plus  or  minus  0.03 
per  cent  (which  are  not  at  all  infrequent)  will  have  a  very  considerable 
influence  upon  the  computations  of  the  respiratory  quotient. 

The  air  analyses  published  by  most  users  of  the  Jaquet  apparatus 
have  shown  discrepancies  in  the  oxygen  content  of  external  air  which 
lead  one  to  suspect  analytical  errors.  We  note  with  interest,  however, 
Hasselbalch's  statement  regarding  his  own  experience  in  analytical 
analysis,  which  indicates  that  he  found  very  insignificant  variations 
in  the  composition  of  the  atmosphere.  Thus  we  may  properly  infer 
an  especially  careful  analytical  procedure.  But  of  more  significance 
is  the  fact  that  Hasselbalch's  published  results  show  us  that  his  carbon- 
dioxide  increment  was  frequently  1  per  cent  or  even  1.5  per  cent.  It 
is  clear  that  Hasselbalch's  analytical  data  are  probably  as  accurate 
as  any  determinations  thus  far  made  of  the  carbon-dioxide  increment 
and  the  oxygen  deficit  in  an  open-circuit  respiration  apparatus,  and  we 
may  have  an  unusual  degree  of  confidence  in  his  values. 

The  number  of  infants  studied  by  Hasselbalch  was  too  few  to  obtain 
definite  physiological  constants,  and  although  he  reports  31  experi- 
mental periods  on  20  infants,  and  as  a  result  of  his  accurate  technique 
was  able  to  make  deductions  from  them,  it  is  obvious  that  a  problem 
so  important  as  the  metabolism  during  the  first  week  of  life  demands 
not  simply  confirmation  but  further  elaboration  of  data.  We  shall 
have  occasion,  in  discussing  our  own  results  subsequently,  to  refer  to 
the  sharply  drawn  conclusions  reported  by  Hasselbalch. 

OBSERVATIONS  BY  WEISS. 

In  1908  G.  Weiss,1  employing  a  type  of  respiration  apparatus  which 
was  entirely  different  from  those  previously  used  for  studying  infant 
metabolism,  made  a  most  interesting  series  of  observations  on  new-born 
infants,  in  which  both  the  carbon-dioxide  output  and  oxygen  intake 
were  studied.  Twelve  new-born  infants  were  observed,  ranging  in 
age  from  1  to  11  days.  His  apparatus  consisted  of  a  metal  chamber 
supplied  with  a  window  and  a  thermometer,  and  having  a  capacity  of 
60  liters.  The  infant  was  hermetically  sealed  in  this  chamber  and 
remained  there  for  approximately  an  hour.  The  air  in  the  chamber  was 
then  thoroughly  mixed  by  an  electric  fan  and  a  sample  taken  for  analy- 
sis. This  method  of  studying  the  gaseous  exchange  was  employed 
by  Chauveau  and  Kaufmann  and  used  with  especial  success  by  Laulanie*. 
The  carbon-dioxide  increment  in  the  chamber  and  the  oxygen  deficit 
could  be  readily  computed  from  the  results  of  the  analysis  and  data 
obtained  as  to  the  total  oxygen  absorption  and  carbon-dioxide  produc- 
tion of  the  infant. 

The  author  points  out  that  with  new-born  infants  the  carbon-dioxide 
excretion  is  two,  three,  or  sometimes  four  times  greater  per  kilogram  of 
body-weight  than  it  is  with  the  adult.  He  found,  for  example,  that  the 
carbon  dioxide  excreted  varied  from  1,064  c.c.  to  337  c.c.  per  kilogram 

1G.  Weiss,  Bui.  de  1'Acad.  M6d.,  1908,  60,  3d  ser.,  p.  458. 


34  PHYSIOLOGY   OF   THE   NEW-BORN   INFANT. 

per  hour,  while  the  values  for  the  oxygen  consumed  varied  from  1,248 
to  404  c.c.  per  hour.  He  also  states  that  he  found  the  respiratory 
quotient  to  be  generally  much  higher  than  the  results  obtained  by 
Scherer.  Basing  his  discussion  upon  the  law  of  surface  area,  Weiss 
concludes  that  the  metabolism  is  proportional  to  the  cube  root  of  the 
square  of  the  weight.  We  give  here  his  argument  in  full.  His  result* 
are  given  in  tables  6  and  7. 

La  consommation  de  divers  sujets  de  m&ne  espece,  et  les  phe"nomenes  qui 
Paccompagnent,  en  particulier  _Pintensite  des  ^changes  respiratoires,  doit 
done  etre  proportionnelle  a  ^P2,  et  en  rapportant  cette  consommation  i 


Punite  de  poids,  on  obtient  —  —  =  —  =  ,  que  je  designerai  par  a. 

Si  done  tous  les  sujets  se  trouvaient  dans  lesmemes  conditions  d'utilisation 
d'oxygene,  ils  devraient,  par  kilogramme,  faire  une  consommation  propor- 
tionnelle a  a.  En  designant  Poxygene  absorbe*  par  kilogramme-heure  par  Q, 

—  serait  constant,  quelle  que  soit  la  taille  du  sujet.  En  suivant  les  variations 
a 

de  —  ,  on  a  reellement  Pindication  d'une  utilisation  surabondante  ou  defec- 
a 

tueuse  de  Poxygene;  c'est  pourquoi  ce  rapport  peut  etre  designe"  par  le  nom 
d'indice  d'oxygenation.  Get  indice  d'oxyge*nation  est  en  somme  le  rapport 
de  ce  qu'un  sujet  prend  reellement  d'oxygene  a  ce  qu'il  devrait  prendre  nor- 
malement  pour  sa  taille. 

En  appliquant  cette  formule  a  Padulte  pendant  le  cycle  de  vingt-quatre 
heures,  P  etant  exprime  en  kilos  et  Q  en  litres,  on  obtient  un  indice  voisin  de 
Pimite*;  0.99  a  1.03,  pour  Phomme  variant  de  60  a  70  kilogrammes. 

Voyons  maintenant  ce  que  Pon  trouve  chez  le  nourrisson. 

J'ai  calcuie  les  indices  correspondant  a  mes  di  verses  determinations  chez 
le  nouveau-ne';  les  r^sultats  sont  reported  dans  la  Table  II.  On  ne  constate 
plus  alors  cet  e*cart  considerable  entre  le  nourrisson  et  Padulte. 

Dans  les  premiers  jours  apr&s  la  naissance,  Pindice  d'oxyg^nation  est  un 
peu  inferieur  a  la  normale,  mais  il  se  releve  ensuite  et  ne  la  de"passe  guere;  chez 
un  seul  sujet  particulierement  beau  il  s'est  e*leye*  a  1.5  et  meme  1.8.  Mes 
mesures  ne  comprennent  pas  les  premieres  heures,  il  y  a  la  une  lacune  a  combler. 

Mais  si,  chez  les  enfants  que  Pon  peut  qualifier  de  normaux,  c'est-a-dire 
qui  augmentent  regulierement  de  poids,  Pindice  d'oxyg^nation  prend  une 
valeur  un  peu  supe*rieure  a  Punite,  chez  les  d^biles  Sieve's  a  la  couveuse  il 
est  franchement  au-dessous,  il  est  au  voisinage  de  0.5  et  ne  se  releve  pas; 
c'est  la  un  point  qui  me  parait  important  et  qu'il  y  a  lieu  d'examiner  de  plus 
pr&s  au  moyen  de  nouvelles  experiences. 

Peut-etre  devrais-je  ni'arr^ter  ici  et  me  contender  des  constatations  que 
j'ai  faites;  mais  il  y  a  lieu  de  se  demander  a  quoi  tiennent  les  differences 
d'indice  que  j'ai  relevees. 

Je  ne  voudrais  pas  sortir  des  limites  de  la  physiologic  normale  et  penetrer 
sur  un  terrain  peu  sur  pour  moi;  cependant  je  tiens  a  faire  une  remarque 
qui  peut  orienter  les  recherches  a  entreprendre. 

Jusque  dans  ces  derniers  temps,  et  confonnement  ^,  la  theorie  de  Lavoisier, 
la  question  de  Pabsorption  d'oxygene  par  les  e*tres  vivants  etait,  sans  restric- 
tion aucune,  intimement  liee  a  la  production  de  Penergie  utilisee  par  les  ani- 
maux. 

Dans  cet  ordre  d'idees  on  aurait  pu  se  demander  si  certains  enfants  ne 
s'oxygenent  pas  plus  que  d'autres  parce  que,  etant  plus  robustes,  ils  s'agitent 
et  depensent  davantage. 


EARLIER   RESEARCHES   W 


fra 


NEW-BORN   INFANTS. 


35 


Mais  cette  explication  ne  peut  pas  nous  contenter;  on  a  vu  en  effet  plus  haut 
que  les  robustes  Femportent  sur  les  debiles  meme  alors  que  les  premiers  dorment 
au  repos  complet  et  que  les  seconds  s'agitent.  En  dehors  de  1'influence  de  Fagi- 
tation,  il  faut  chercher  une  autre  cause  a  la  variation  de  1'indice  d'oxyge*nation. 

Au  cours  de  recherches  que  je  poursuis  depuis  plusieurs  anne"es,  et  dont 
j'ai  public  quelques  resultats  a  la  Societe  de  Biologic,  j'ai  montre  que  non 
seulement,  comme  on  le  savait,  certains  animaux  pouvaient  yivre  un  certain 
temps  a  Fabri  de  Pair,  y  produisant  du  travail  avec  elimination  d'acide  car- 
bonique,  mais  que  cette  production  de  travail  ne  se  faisait  pas  aux  de*pens  de 
provisions  d'oxygene  tiroes  anterieurement  de  F  atmosphere. 

Le  muscle  peut  travailler  sans  intervention  de  Foxygene  de  Fair.  Celui-ci 
ne  semble  intervenir  que  pour  eViter  Fencombrement  de  Forganisme  par  des 
de*chets  et  produits  toxiques.  Autrement  dit,  Foxygene  est  un  e"purateur. 

II  se  peut  qu'il  y  ait  lieu  de  rapprocher  ce  role  epurateur  de  Foxygene  des 
bonnes  conditions  de  developpement  des  enfants  robustes,  tandis  qu'il  est 
insuffisant  chez  les  debiles. 

TABLE  6.1 


Nos. 

Age. 

Poids. 

CO2 

02 

R.Q. 

Remarques. 

I.    9  BON  fiTAT. 

1 
2 
3 

4 
5 

6 

7 

5e  jour. 

3.120 

0.960 
0.887 
0.975 
1.064 
0.922 
0.884 
0.556 

1.067 
0.935 
1.023 
1.248 
0.971 
0.912 
0.598 

0.90 
0.95 
0.95 
0.90 
0.95 
0.97 
0.93 

22°.         Vient  de  teter.     Cris  frequents. 
22  .  5°.     Cris  frequents. 
23  .  5°.     Cris  frequents. 
24°.         Cris  frequents. 
21°.         Tete  il  y  a  2  h.  30.    Cris  frequents. 
21.5°.     Vient  de  teter. 
21.5°.     Repos  complet. 

8e  jour. 

3.370 

II.  rf1  BON  &TAT. 

8 
9 
10 
11 
12 
13 
14 
15 
16 

17 

2e  jour. 

3.300 

0.403 
0.530 
0.604 
0.613 
0.701 
0.753 
0.659 
0.756 
0.815 

0.837 

0.498 
0.631 
0.695 
0.730 
0.779 
0.801 
0.701 
0.796 
0.886 

0.854 

0.81 
0.84 
0.87 
0.84 
0.90 
0.94 
0.94 
0.95 
0.92 

0.98 

21°.         Aucune  tetee  encore.     Sommeil. 
21.5°.     Quelques  cris. 
21°.         Vient  de  teter.     Sommeil. 
Sommeil. 
22°.         Vient  de  teter.    Repos  et  sommeil. 
23°.         Sommeil. 
23.5°.     Vient  de  teter.     Sommeil. 
26°.         Cris,  puis  sommeil. 
24°.         Vient  de  teter.     Cris.     Demi-som- 
meil. 
24  .  5°.     Demi-sommeil. 

4e   jour. 

3  270 

7e   jour. 

3.420 

9e   jour. 

3.520 

lie   jour. 

3.620 

III.    9  BON  fiTAT. 

18 
19 
20 
21 
22 
23 
24 

25 

2«  jour. 

3.570 

0.403 
0.413 
0.407 
0.525 
0.629 
0.596 
0.696 

0.589 

0.504 
0.504 
0.509 
0.610 
0.732 
0.678 
0.757 

0.685 

0.80 
0.82 
0.80 
0.86 
0.86 
0.88 
0.92 

0.86 

24°.         Vient  de  teter.     Sommeil. 
25°.         Sommeil. 
23°.         Vient  de  teter.     Sommeil. 
25  .  5°.     Cris  et  sommeil. 
24  .  5°.     Vient  de  teter.    Cris  et  sommeil. 
26°.         Cris  et  sommeil. 
22°.         Pas  tete  ce  matin.     Sommeil.    Re- 
veil.     Cris. 
22°.         Tetee.     Sommeil. 

4e  jour. 

3.600 

6e  jour. 

3.710 

9e  jour. 

3.860 

IV.    $  BON  fiTAT. 

26 
27 
28 
29 

2e  jour. 

3.050 

0.469 
0.579 
0.479 
0.451 

0.579 
0.697 
0.614 
0.609 

0.81 
0.83 
0.78 
0.74 

22  .  5°.     Aucune  tetee  encore.     Sommeil. 
24°.         Reveil  et  pleurs. 
23°.         Vient  de  teter.     Sommeil. 
24°.         Sommeil. 

4e  jour. 

2.780 

xTable  I  in  the  Weiss  article. 


36  PHYSIOLOGY   OF   THE   NEW-BOKN   INFANT. 

TABLE  61 — Continued. 


Nos. 

Age. 

Poids. 

C02 

02 

R.  Q. 

Remarques. 

2V.  cf  JUMEAU  DfiBILE  A  LA  COUVEUSE. 

30 
31 
32 
33 

4e  jour. 
6e  jour. 
9e  jour. 
11®  jour. 

1.570 
1.530 
1.470 
1.480 

0.443 
0.337 
0.408 
0.364 

0.554 
0.481 
0.517 
0.444 

0.80 
0.70 
0.79 
0.82 

23  .  5°.     Legere  agitation  et  sommeil. 
24  .  5°.     Sommeil. 
25°.         L6gere  agitation  et  sommeil. 
23  .  5°.     Sommeil  leger  avec  frequents  mouve- 
ments. 

VI.  d*  BON  6TAT. 

34 
»35 

2®  jour. 
5e  jour. 

3.070 
2.900 

0.403 
0.401 

0.492 
0.521 

0.82 
0.77 

24  .  5°.     Pas  tete  ce  matin.     Sommeil. 
26°.         Vient  de  teter.     Sommeil. 

VII.  d*  BON  fiTAT. 

36 
37 

38 
39 

40 

2e   jour. 
4®   jour. 

7e   jour. 
9e  jour. 

lie  jour. 

2.470 
2.250 

2.320 
2.370 

2.430 

0.406 
0.551 

0.556 
0.565 

0.685 

0.556 
0.771 

0.670 
0.698 

0.753 

0.73 
0.72 

0.83 
0.81 

0.91 

24  .  5°.     Aucune  tetee  encore.    Sommeil  leger  . 
25.5°.     Petite  tetee  le  matin.     Demi-som- 
meil. 
23°.         Vient  de  teter.     Sommeil. 
23°.         Tete  il  y  a  trois  heures.     Quelques 
cris.     Sommeil. 
21°.         Quelques  pleurs.     Sommeil. 

«VIII.    9  Nfi  A  8  MOIS.     DfiBILE.     COUVEUSE. 

41 
42 
43 

4®  jour. 
6e  jour. 
8e  jour. 

1.860 
1.850 
1.790 

0.425 
0.349 
0.514 

0.518 
0.459 
0.591 

0.82 
0.76 
0.87 

23  .  5°.     Cris  la  moitiS  du  temps. 
25°.         Quelques  pleurs.     Sommeil. 
23  .  5°.     Sommeil  et  cris. 

IX.    9  BON  fiTAT. 

44 
45 
46 
47 

ler  jour. 
3°  jour. 
5e   jour. 
106  jour. 

3.200 
3.000 
3.030 
3.150 

0.342 
0.341 
0.555 
0.638 

0.433 
0.421 
0.646 
0.701 

0.79 
0.81 
0.86 
0.91 

26°.         Sommeil  continu. 
27°.         Vient  de  teter.     Sommeil  continu. 
27°.         Quelques  cris.     Sommeil. 
23  .  5°.     Quelques  cris.     Sommeil. 

X.  d"  BON  fiTAT. 

48 

49 
50 
51 

ler  jour. 

4e   jour. 
6e   jour. 
8e   jour. 

3.700 

3.450 
3.530 
3.550 

0.404 

0.447 
0.545 
0.664 

0.481 

0.552 
0.641 
0.772 

0.84 

0.81 
0.85 
0.86 

25.5°.     Aucune  tetee  encore.     Sommeil  un 
peu  agite. 
23°.         Vient  de  teter.     Sommeil. 
23  .  5°.     Vient  de  teter.     Demi-sommeil. 
23°.         Vient  de  teter.     Cris  frequents. 

XL  <?  BON  fiTAT. 

52 

53 
54 

2e  jour. 

4e   jour. 
6e  jour. 

3.600 

3.450 
3.550 

0.543 

0.521 
0.625 

0.647 

0.606 
0.680 

0.84 

0.86 
0.92 

23°.         Vient  de  teter.     Reveil  tranquille. 
Quelques  cris. 
23°.         Vient  de  teter.     Sommeil. 
24.5°.     Vient  de   teter.     Vagissements  et 
sommeil. 

6XII.  d*  DfiBILE  A  LA  COUVEUSE. 

55 
56 
57 

58 

59 

ler  jour. 
3e   jour. 
5e  jour. 
8e   jour. 

10®  jour. 

1.950 
1.800 
1.800 
1.790 

1.820 

0.327 
0.381 
0.351 
0.465 

0.512 

0.404 
0.465 
0.423 
0.495 

0.539 

0.81 
0.82 
0.83 
0.94 

0.95 

26°.         Aucune  tetee  encore.     Sommeil. 
26°.         Quelques  mouvements.     Sommeil. 
26  .  5°.     Sommeil. 
24°.         Vient  de  teter.    Sommeil  et  quelques 
cris. 
23.5°.     Vient  de  teter.     Demi-sommeil  et 
reveil. 

I  in  the  Weiss  article. 
*La  mere  n'ayant  pas  assez  de  lait,  cet  enfant  recevait  en  supplement  sept  repas  de  30  grammes 

de  lait  sterilised     Dernier  repas  trois  heures  avant  1'experience. 
*La  mere  n'a  pas  permis  la  continuation  des  mesures. 
4L' enfant  tetait  environ  deux  heures  avant  1'experience. 
5Jusqu'au  huitieme  jour,  cet  enfant,  trop  faible  pour  teter,  prenait  au  bol,  toutes  les  deux  heures, 

10  grammes  de  lait  provenant  de  la  mere  les  deux  premiers  jours,  puis  les  jours  suivants  30 

grammes  toutes  les  2  h.  30  min. 


EARLIER   RESEARCHES  WITH   NEW-BORN   INFANTS. 
TABLE  7. — Indices  d'oxygenation.1 


37 


Robustes. 

Debiles. 

I2 

II 

III 

IV 

VI 

VII 

IX 

X 

XI 

V 

VIII 

XII 

.574 

0.742 

0.771 

0.840 

0.718 

0.751 

0.639 

0.745 

0.993 

0.642 

0.637 

0.503 

.380 

0.940 

0.771 

1.011 

0.742 

1.010 

0.606 

0.836 

0.918 

0.552 

0.562 

0.565 

.509 

.051 

0.779 

0.863 

0.888 

0.937 

0.974 

1.037 

0.584 

0.715 

0.514 

.841 

.084 

0.933 

0.856 

0.932 

1.030 

1.177 

0.506 

" 

0.599 

.465 

.176 

1.134 

1.013 

0.657 

.368 

.210 

1.051 

" 

0.897 

.066 

1.189 

11 

" 

.210 

1.075 

" 

" 

.360 

" 

" 

.311 

" 

II  in  the  Weiss  article. 
2Les  nombres  de  la  premiere  colonne  (I)  ne  commencent  pas  aux  premiers  jours  apres 
la  naissance. 

It  is  obvious  that  the  results  recently  reported  from  this  laboratory 
on  the  heat-output  of  atrophic  infants  confirm  the  observations  of 
Weiss,  but  the  existence  of  abnormalities  in  the  nature  of  the  oxidative 
processes  is  hardly  essential  to  explain  these  differences.  The  varia- 
tions in  body  composition  and  the  variations  in  cellular  and  muscular 
activity  fully  account  for  all  differences  in  the  amounts  of  oxygen 
consumed. 

OBSERVATIONS  BY  BIRK  AND  EDELSTEIN. 

Using  the  Pettenkofer-Voit  respiration  apparatus  in  the  Kaiserin 
Auguste  Victoria-Haus  in  Charlottenburg,  Birk  and  Edelstein1  in  1910 
studied  the  total  carbon-dioxide  output  of  a  healthy  new-born  infant 
weighing  3,200  grams  and  50  cm.  long,  during  the  first  3  days  of  post- 
natal life.  As  the  authors  themselves  recognize,  the  lack  of  data 
regarding  the  oxygen  consumption  makes  it  impossible  to  use  the  results 
for  discussing  the  character  of  the  katabolism  during  the  first  days  of 
life.  The  absence  of  a  quantitative  measurement  of  the  muscular 
activity  likewise  makes  it  difficult  to  compare  their  results  with  data 
obtained  in  researches  in  which  the  muscular  activity  was  observed. 

OBSERVATIONS  BY  CARPENTER  AND  MURLIN. 

Employing  the  differential  method,  Carpenter  and  Murlin2  made 
observations  with  the  bed  respiration  calorimeter  in  the  Nutrition 
Laboratory  on  pregnant  women  before  and  after  delivery.  By  deduct- 
ing the  metabolism  of  the  mother  after  delivery  from  that  of  the  mother 
and  child,  an  attempt  was  made  to  estimate  the  total  metabolism  of 
the  new-born  infant.  It  is  obvious  that  the  difficulties  inherent  in  a 
differential  method  of  this  type  make  the  results  of  little  value  for  direct 
comparison  with  data  obtained  with  new-born  infants. 


and  Edelstein,  Monatsschr.  f.  Kinderheilk.,  1910,  9,  p.  505. 
2Carpenter  and  Murlin,  Archives  Internal  Med.,  1911,  7,  p.  184. 


38  PHYSIOLOGY   OF   THE   NEW-BORN   INFANT. 

OBSERVATIONS  BY  BAILEY  AND  MURLIN. 

In  an  earlier  publication  of  our  work,  in  which  we  specifically  con- 
sidered the  influence  of  the  age  of  an  infant  upon  the  metabolism 
per  square  meter  of  body-surface,  we  computed  the  average  values  for 
9  new-born  infants  ranging  in  age  from  3  hours  to  14  days.1  These 
results  were  presented  solely  for  the  purpose  of  discussing  the  heat 
production  per  square  meter  of  body-surface  in  connection  with  similar 
measurements  obtained  with  a  large  number  of  atrophic  as  well  as 
normal  infants.  Subsequently  Bailey  and  Murlin2  discussed  the 
energy  requirements  of  new-born  infants,  chiefly  upon  the  basis  of  our 
values,  supplemented  by  their  own  fragmentary  data.  It  is  unneces- 
sary here  to  enter  into  a  discussion  of  their  results,  for  in  the  light  of  the 
researches  of  Hasselbalch,  their  investigation  can  hardly  be  looked  upon 
as  more  than  a  substantiation  of  the  earlier  research. 

PURPOSE  AND  PLAN  OF  THE  RESEARCH. 

The  incomplete  nature  of  all  of  the  earlier  work  with  new-born 
infants  and,  indeed,  of  most  of  the  recent  studies,  the  lack  of  apprecia- 
tion of  the  significance  of  muscular  repose  during  the  determination  of 
the  total  metabolism,  and  the  usually  imperfect  technique  for  the 
measurement  of  the  oxygen  consumption,  with  the  consequent  liability 
to  error  in  the  estimation  of  the  respiratory  quotient,  have  led  us  to 
believe  that  an  extended  study  of  a  large  number  of  new-born  infants, 
in  which  the  metabolism  during  the  first  week  of  post-natal  life  should 
be  definitely  established,  was  not  only  justifiable,  but  that  the  results 
would  be  of  great  significance. 

APPARATUS  AND  TESTS  FOR  ACCURACY. 

The  respiration  apparatus  which  was  described  in  our  previous 
reports  of  studies  on  infant  metabolism3  and  which  has  been  installed 
at  the  Massachusetts  General  Hospital  since  January  1913,  was 
employed  for  the  measurement  of  the  respiratory  exchange  of  infants 
during  the  first  week  after  birth.  The  tightness  of  the  apparatus  was 
tested  each  day  to  demonstrate  the  absence  of  any  leakage  of  air  which 
might  affect  the  oxygen  measurements.  In  addition  check  tests  were 
frequently  made  in  which  the  respiratory  quotient  of  alcohol  was  used 
as  an  index  of  accuracy.  In  consequence  we  are  confident  that  the  appa- 
ratus was  absolutely  tight  throughout  the  whole  series  of  observations. 

We  wish,  however,  distinctly  to  disclaim  absolute  accuracy  for  all 
of  the  individual  respiratory  quotients,  for  with  a  series  of  observa- 
tions including  approximately  1,000  periods  and  extending  over  18 
months,  it  is  impossible  to  insure  absolute  accuracy  for  the  individual 

Benedict  and  Talbot,  Am.  Journ.  Diseases  of  Children,  1914,  8,  p.  1,  tables  13  and  15. 
*Bailey  and  Murlin,  Am.  Journ.  Obstetrics,  1915,  71,  p.  526. 

•Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  201,  1914,  p.  32;  also  Benedict  and  Talbot, 
Am.  Journ.  Diseases  of  Children,  1914,  8,  p.  21. 


PURPOSE   AND   PLAN   OF   RESEARCH.  39 

periods  of  observation.  That  at  times  inconceivably  low  respiratory 
quotients  are  found  among  the  data  is  not  surprising.  The  difficulties 
of  determining  accurately  the  exact  temperature  of  the  air  in  the  appa- 
ratus, particularly  when  the  infant  is  restless,  needs  no  special  emphasis. 
Similarly,  the  equalization  of  humidity  throughout  the  chamber  with  no 
specific  ventilation  other  than  that  supplied  by  the  air-current  likewise 
presents  technical  difficulties.  The  results  as  a  whole  are,  we  believe, 
accurate  and  may  be  accepted  without  question.  It  seems  fitting, 
therefore,  to  present  the  data  exactly  as  recorded,  even  though  occa- 
sionally there  may  be  anomalous  differences  in  the  values,  rather  than 
to  attempt  an  arbitrary  selection  which  might  favor  our  interpretation 
of  the  results.  While  we  have  given  our  data  completely,  without 
selection  and  without  reservation,  the  fact  should  be  emphasized  that 
individual  quotients  must  not  be  interpreted  as  significant.  It  was 
our  purpose  to  collect  such  a  large  mass  of  results  that  the  general 
picture  of  both  the  character  and  the  amount  of  the  metabolism  during 
the  first  week  of  post-natal  life  would  be  perfectly  defined  and  clear. 

METHOD  OF  COMPUTATION. 

The  details  of  the  experimental  routine  and  of  the  technique  may  be 
found  in  the  publication  describing  our  earlier  study.1  As  it  appears 
to  be  difficult  for  certain  writers  to  understand  the  method  of  comput- 
ing the  results  obtained  in  observations  of  this  character,  it  seems  desir- 
able to  describe  our  method  of  calculation  somewhat  more  fully  than 
has  previously  been  done. 

In  the  determination  of  the  respiratory  exchange  by  an  apparatus  of 
the  type  we  employed,  it  is  obvious  that  the  carbon-dioxide  output  in 
short  periods  may  be  determined  more  exactly  than  the  oxygen  intake. 
The  residual  amount  of  carbon  dioxide  in  the  chamber  remains  constant 
from  period  to  period,  the  mechanism  supplying  the  purified  air  being 
so  adjusted  as  to  replace  the  air  in  the  chamber  some  15  times  during 
a  30-minute  period.  On  the  other  hand,  the  determination  of  the 
oxygen  consumption  involves  the  calculation  of  the  volume  of  air 
residual  in  the  chamber  at  the  end  of  each  period.  This  calculation 
requires  an  exact  knowledge  of  the  average  temperature  and  the  degree 
of  humidity  of  the  air  at  the  end  of  each  period  of  measurement.  As 
has  already  been  pointed  out,  the  determination  of  these  factors 
presents  great  technical  difficulties.  Since  the  longer  the  period  of 
measurement  the  less  the  errors  influence  the  results,  it  has  been  our 
custom  to  measure  the  carbon  dioxide  in  30-minute  periods,  with,  so 
far  as  possible,  complete  muscular  repose  on  the  part  of  the  infant,  and 
to  calculate  the  oxygen  intake  only  once  for  the  entire  time  that  the 
child  remains  in  the  respiration  chamber.  It  may  reasonably  be 
assumed  that  differences  in  the  muscular  activity,  especially  with  the 

Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1914,  p.  31. 


40  PHYSIOLOGY   OF  THE   NEW-BORN   INFANT. 

new-born  infant,  will  not  cause  a  marked  difference  in  the  character 
of  the  katabolism  so  that  when  a  comparison  is  made  of  the  carbon- 
dioxide  production  and  the  oxygen  consumption  for  the  entire  period 
of  observation,  i.e.,  If  to  2  hours,  the  result  may  be  fairly  considered  as 
representing  the  average  respiratory  quotient  for  that  period.  If 
in  this  time  there  is  a  30-minute  period  of  complete  muscular  repose 
during  which  the  carbon-dioxide  output  has  been  measured,  the  heat- 
output  may  be  computed  for  this  minimum  period  by  the  method  of 
indirect  calorimetry,  i.  e.,  by  multiplying  the  carbon-dioxide  production 
for  the  30-minute  period  by  the  calorific  equivalent  of  carbon  dioxide 
for  the  respiratory  quotient  prevailing  during  the  entire  period  of  1^ 
to  2  hours. 

The  heat  output  for  the  entire  period  of  observation  may  be  obtained 
not  only  by  using  the  carbon-dioxide  production  for  that  period,  but 
may  also  be  secured  by  multiplying  the  oxygen  consumption  by  the 
calorific  equivalent  of  oxygen  for  the  respiratory  quotient  during  the 
period  of  observation.  In  view  of  the  technical  difficulties  of  meas- 
uring the  oxygen  consumption,  however,  this  factor  may  not  properly 
be  used  for  calculating  the  heat-output  for  the  minimum  period.1 

It  may  be  argued  that  the  assumption  of  a  representative  respiratory 
quotient  for  the  entire  period  of  observation  for  use  in  computing  the 
heat-output  during  the  minimum  period  may  lead  to  error,  since  there 
may  be  a  slight,  normal  fall  in  the  respiratory  quotient  (particularly 
if  the  observation  is  preceded  by  nursing),  this  fall  being  due  to  the  fact 
that  the  carbohydrate  of  milk  probably  burns  more  rapidly  than  the 
fat  and  the  protein.  It  is  fair  to  assume,  however,  that  the  error  caused 
by  the  use  of  this  average  respiratory  quotient  in  the  formula  for  indi- 
rectly computing  the  heat-output  from  the  carbon-dioxide  production 
for  a  30-minute  period  is  certainly  no  greater  and  is  probably  less  than 
that  involved  in  the  direct  measurement  of  the  oxygen  consumption 
with  its  attendant  temperature  and  barometric  measurements  at  the 
beginning  and  end  of  the  period.  In  our  research  we  desired  not  only  to 
determine  the  character  of  the  katabolism,  but  also,  if  possible,  to  deter- 
mine the  minimum  basal  metabolism.  Since  this  was  usually  deter- 
minable  only  in  30-minute  periods,  the  method  of  computation  just 
outlined  was  applied  to  these  experiments. 

xlt  should  be  said  that  the  proper  thermometer,  barometer,  psychrometer,  spirometer,  and  meter 
readings  were  recorded  at  the  end  of  every  period.  Calculations  based  upon  these  showed  for  the 
most  part  good  agreement  in  each  period  between  the  heat  indirectly  calculated  from  the  carbon- 
dioxide  output  and  the  average  respiratory  quotient  and  that  calculated  from  the  oxygen  consump- 
tion and  the  average  respiratory  quotient.  This  fact  has  been  cited  in  discussing  the  maximum 
heat-output  (see  table  18,  p.  113).  Nevertheless,  as  each  absolute  value  for  the  oxygen  determina- 
tion may  possibly  be  subject  to  the  errors  previously  cited,  the  values  for  the  heat-output  in  this 
publication,  except  in  table  18,  have  been  calculated  from  the  carbon-dioxide  determinations, 
using  the  calorific  value  of  carbon  dioxide  corresponding  to  the  average  respiratory  quotient  for 
the  entire  sojourn  inside  the  chamber. 


PURPOSE   AND   PLAN   OF   RESEARCH.  41 

CARE  OF  THE  NEW-BORN  INFANT. 

The  general  routine  followed  at  the  Boston  Lying-in  Hospital  for 
the  care  of  infants  during  and  after  delivery  is  as  follows : 

The  infant  is  delivered  in  the  "case  room"  of  the  hospital.  This 
room  is  kept  at  a  temperature  of  80°  to  84°  F.  Ordinarily,  after  the 
baby  is  delivered,  it  is  held  up  by  the  feet  in  order  to  drain  the  mucus 
from  its  mouth  and  throat.  About  one  out  of  five  babies  is  patted  on 
the  back  to  make  it  cry  and  in  this  way  to  expand  the  lungs.  The  cord 
is  then  cut,  tied  with  two  ligatures,  and  sterile  dressings  applied. 
These  dressings  consist  of  two  sterile  sponges,  one  of  which  is  put 
around  the  cord  and  the  other  over  the  cord.  The  dressings  are 
held  in  place  by  a  gauze  band  placed  over  them.  The  infant  is  laid 
in  a  crib  on  its  right  side,  with  a  blanket  so  folded  about  it  as  to  cover 
the  entire  body,  and  with  the  feet  slightly  elevated,  so  that  the  mucus 
may  continue  to  drain  from  the  mouth.  A  tin  heater,  with  a  tempera- 
ture of  about  100°  F.  and  covered  with  Canton  flannel,  is  then  put  at 
the  baby's  back  at  such  distance  that  a  hand  can  be  placed  between  the 
heater  and  the  body  of  the  infant.  The  baby  is  left  in  the  crib  for  1J 
to  2  hours  after  birth,  while  the  nurse  is  caring  for  the  mother.  As 
soon  as  the  nurse  is  free,  the  baby  is  bathed  in  cotton-seed  oil.  The 
temperature  of  the  oil  is  not  known,  but  the  nurse  says  that  it  is  "kept 
warm"  and  is  probably  the  same  temperature  as  that  of  the  room 
(80°  to  84°  F.)  or  a  little  warmer.  After  the  oil-bath,  the  infant  is 
powdered  with  castile  soap  and  washed  in  sterile  water,  the  temperature 
of  the  bath  being  about  100°  F.  The  exposure  to  the  air  is  in  all  about 
15  minutes,  this  including  the  oiling,  bathing,  and  weighing. 

The  infant  is  next  taken  to  the  "ward  room,"  which  has  a  tempera- 
ture of  68°  to  74°  F.,  and  put  in  its  crib,  where  it  remains  until  it  is 
nursed.  It  is  first  put  to  the  breast  8  hours  after  birth  and  subsequently 
every  6  hours  during  the  first  24  hours,  the  nursing  period  being  3  to 
4  minutes.  Some  babies  take  hold  of  the  nipple  and  nurse  immedi- 
ately, while  others  are  lazy  and  have  to  be  urged  by  the  attendant. 
During  the  second  day  the  baby  is  put  to  the  breast  every  4  hours  and 
is  left  there  3  to  4  minutes.  In  the  third  24  hours,  the  baby  is  nursed 
every  2  hours  during  the  day  and  every  4  hours  during  the  night, 
thus  making,  in  all,  10  feedings.  When  the  milk  secretion  is  once 
established,  i.  e.,  when  "the  milk  comes  in,"  the  baby  is  left  at  the 
breast  10  minutes  at  each  feeding. 

This  routine  was  varied  somewhat  when  the  infants  were  taken  to 
the  respiration  apparatus  within  an  hour  of  birth.  An  extra  nurse 
took  the  baby  after  delivery  and  oiled,  bathed,  and  dressed  it  as  pre- 
viously described.  It  was  then  wrapped  in  two  or  three  blankets, 
the  number  varying  with  the  weather.  The  blankets  were  drawn  up  so 
as  to  form  a  hood  almost  entirely  covering  the  infant's  head  and  the 
baby  was  then  carried  in  the  nurse's  arms  from  the  Lying-in  Hospital  to 


42  PHYSIOLOGY   OF   THE   NEW-BORN   INFANT. 

the  Massachusetts  General  Hospital.  The  distance  between  the  front 
doors  of  these  two  hospitals  is  177  paces  and  not  more  than  2  or  3 
minutes  are  required  to  go  from  one  building  to  the  other.  On  reaching 
the  observation  room,  the  baby  was  placed  in  the  respiration  chamber. 
When  the  measurements  of  the  respiratory  exchange  were  completed, 
the  baby  was  weighed  and  measured  and  then  returned  immediately 
to  the  Lying-in  Hospital. 

The  routine  followed  for  one  infant  which  was  studied  shortly  after 
birth  is  shown  by  the  notes  given  below  and  is  fairly  typical  of  the 
routine  used  for  the  infants  studied  under  these  circumstances. 

Baby  R.  (No.  94),  negro— Born  at  2h  12m  p.  m.,  April  28,  1915.  Low  for- 
ceps case.  Message  received  at  the  observation  room  at  2h  20m  p.  m.  Baby 
received  in  the  case  room  at  2h  27m  p.  m.  It  had  been  exposed  at  birth  3  to 
4  minutes.  This  exposure  was  less  than  usual,  as  the  mother  had  a  hemor- 
rhage and  required  immediate  attention.  The  cord  was  therefore  simply 
clamped.  Usually  the  baby  lies  in  the  physician's  lap  6  to  8  minutes  before 
the  cord  is  cut.  The  infant  was  also  exposed  about  5  minutes  shortly  after 
birth  while  it  was  being  immersed  in  water  of  a  temperature  of  100°  to  105°  F., 
and  wrapped  in  warm  blankets  with  heaters.  At  2h  30m  p.  m.  it  was  exposed 
for  3  or  4  minutes  when  the  cord  was  ligated  and  cut.  The  infant  was  then 
weighed,  oiled,  and  the  length  measured,  this  requiring  5  minutes.  The  cord 
was  dressed,  the  band  applied,  and  the  baby  dressed  in  the  period  of  5  minutes. 
A  bonnet  and  small  coat  were  put  on  the  infant,  which  was  also  wrapped  in 
two  large  blankets.  The  nurse  and  baby  left  the  Lying-in  Hospital  about 
2h  55m  p.  m.  and  arrived  in  the  observation  room  in  the  Massachusetts  General 
Hospital  at  3  p.  m.,  where  a  study  was  made  of  the  respiratory  exchange. 


STATISTICS   OF   OBSERVATIONS.  43 

STATISTICS  OF  THE  OBSERVATIONS. 

The  clinical  statistics  of  the  105  infants  studied  hi  this  research 
are  given  in  table  8,  with  full  data  regarding  birth. 

The  results  of  the  observations  on  the  gaseous  exchange  of  the  same 
infants  are  given  in  chronological  order  in  table  9.  The  infants 
included  in  this  research  are  referred  to  throughout  by  numbers,  but 
in  the  first  column  of  this  table  the  initials  have  also  been  given  for 
such  of  the  infants  as  were  included  in  the  previous  report.1  The 
sex  and  the  dates  of  the  individual  observations  are  given  in  the  next 
two  columns.  The  length  of  the  infant  in  centimeters,  also  the  age  and 
weight  for  each  observation,  are  given  in  succeeding  columns,  and  the 
actual  length  of  each  period  from  which  the  per  hour  figures  are  calcu- 
lated is  given  under  " Duration  of  period."  The  data  for  the  prelim- 
inary periods,  i.  e.,  the  carbon  dioxide  produced  per  hour  and  the  pulse- 
rate,  are  shown  by  the  first  values  given  for  each  observation.  These 
values  were  not  used  in  calculating  the  respiratory  quotient  for  the  whole 
observation,  only  those  in  brackets  (if  more  than  one  period  was  used) 
being  included  in  this  calculation.  The  heat-production  per  24  hours 
is  given  on  the  three  bases  of  total  heat-production  and  heat-production 
per  kilogram  of  body-weight  and  per  square  meter  of  body-surface. 
The  pulse-rate  is  an  average  value  for  the  several  counts  made  during 
each  period.  The  data  for  the  rectal  temperature  represent  the  records 
made  at  the  beginning  and  end  of  the  observations.  Prior  to  November 
1914  the  body-temperature  was  recorded  about  30  minutes  before  the 
measurement  of  the  metabolism  began.  After  November  1914  the 
record  was  made  approximately  3  minutes  before  the  beginning  of 
the  preliminary  period  of  observation;  this  was  always  the  routine 
with  the  very  young  infants  in  the  later  observations.  Temperature 
records  were  usually  taken  within  5  minutes  after  the  end  of  the 
observation  and  always  within  10  minutes.  The  data  regarding  the 
feeding  show  the  time  between  the  taking  of  food  and  the  beginning 
of  the  metabolism  measurements,  also  the  kind  and  composition  of  the 
food.  Nearly  all  of  the  infants  were  normal,  but  a  few  were  patho- 
logical cases,  these  being  indicated  in  the  notes  accompanying  the  table. 

Benedict  and  Talbot,  Am.  Journ.  Diseases  of  Children,  1914,  8,  p.  1,  tables  13  and  15. 


44 


PHYSIOLOGY   OF   THE   NEW-BORN   INFANT. 


TABLE  8. — Clinical  statistics  of  infants. 


Sub- 
ject 
No. 

Sex. 

Date  of 
birth. 

Birth. 

Term. 

Delivery. 

Birth-weight. 

Length. 

1 

2 
3 
4 
5 
6 
7 
8 
9 
10 
11 
12 
13 
14 
15 
16 
17 
18 
19 
20 
21 
22 
23 
24 
25 
26 
27 
28 
29 
30 
31 
32 
33 
34 
35 

36 
37 
38 
39 
40 
41 
42 
43 
44 
45 
46 
47 
48 
49 
50 
51 

M. 

F. 
M. 
F. 
M. 
M. 
M. 
M. 
F. 
M. 
M. 
F. 
F. 
M. 
M. 
F. 
F. 
M. 
M. 
F. 
F. 
F. 
F. 
M. 
M. 
F. 
M. 
F. 
F. 
M. 
M. 
M. 
M. 
F. 
F. 

M. 
F. 
F. 
F. 
F. 
M. 
F. 
F. 
F. 
F. 
M. 
M. 
F. 
F. 
F. 
M. 

1913 
Dec.    3 

1914 
Jan.     8 
Mar.  16 
Mar.  22 
Mar.  30 
Mar.  31 
...do.... 
Apr.     6 
Apr.     9 
Apr.  11 
Apr.  15 
Apr.  18 
Apr.  21 
Apr.  27 
May    3 
May    5 
May  11 
...do  

Primiparous.  .  . 

Multiparous.  . 
Primiparous.  .  . 
Multiparous.  . 
do  
do  
Primiparous.  .  . 

Full  term... 

do  
do  
do  
do  
do  

Csesarian  sec- 
tion. 

Normal 

Ibs.    oz. 

*8      5* 
8     14 
7     15 
8      6£ 
10       2 
g 

kilo* 
13.13 

23.79 
4.03 
3.60 
3.81 
4.59 
3.63 
3.63 
4.41 
3.63 
4.07 
3.95 
43.37 
4.22 
3.77 
4.11 
3.67 
3.18 
3.57 
3.86 
3.15 
2.86 
3.69 
2.35 
3.40 
3.63 
3.86 
3.73 
3.63 
3.57 
3.70 
3.60 
4.11 
3.26 
4.82 

3.52 
2.49 
4.20 
2.95 
2.92 
3.91 
4.25 
3.94 
3.57 
2.66 
3.83 
4.05 
4.82 
2.92 
3.09 
4.03 

cm. 
52 

53 
52 
46.5 
52.5 
52 
51.5 
51 
51 
52 
52 
52.5 
50 
51 
50 
53 
52.5 
50.5 
53 
52 
50 
49 
50.5 
43 
51.5 
50 
52 
50.5 
50 
51 
53.5 
47.5 
52 
50.5 
54 

53 
46.5 
51.5 
50 
49.5 
51.5 
54 
50 
51 
46.5 
51.5 
52 
54.5 
47.5 
48.5 
52.5 

do  
do  
Low  forceps.  .  . 
Normal  

do 

Multiparous.  . 
do  

..do.. 
do     .    . 

do  
do     .    .    . 

8     .. 
9     Hi 

8     .  . 

Primiparous.  .  . 

do  

do  

Multiparous.  . 
do  
Primiparous.  .  . 
Multiparous.  . 
Primiparous.  .  . 
Multiparous.  . 

do  
do  
do  
do  
do  
.    ..do. 

do  
do  
do  
do  
do  
do 

8     15i 
8     Hi 

47       7 

9       5 
8       5 
9       1 
8       li 

7     14 
8       8 
6     15 
6       5 
8       2 
5       3 
7       8 
8     .. 
8       8 
8       3i 
8     .. 
7     14 
8      2i 
7     15 
9       1 
7      3 
10     10 

7     12 
5       8 
9       4 
6       8 
6       7 
8     10 
9       6 
8     11 
7     14 
5     14 
8      7 
8     15 
10     10 
6       7 
6     13 
8     14 

.    ..do  

do...    . 

.    .  do.    .    .    . 

..    ..do  

do  

.    ..do.    .    .    . 

May  17 
May  24 
...do.... 
May  31 
...do.... 
June    7 
...do  

do  
do  
do  
do  
Primiparous.  .  . 
do  
..do  

do  
do  
do  
do  
do  
Premature6  . 
Full  term  .    . 

do  
do  
do  
do  
do  
do  
do  

June    6 
June  15 
June  17 
June  24 
...do.... 
Oct.    15 
Oct.    19 
Oct.   23 
Oct.   24 
Oct.   29 

Nov.    1 
Nov.    3 
Nov.    9 
..do  . 

Multiparous.  . 
do  
do  
do  
Primiparous.  .  . 
Multiparous.  . 
Primiparous.  .  . 
Multiparous.  . 

do  
do  
do  
do  
do  
do  
do.    .    . 

do  
do  
do  
do  
do  
do  
Low  forceps.  .  . 
Normal  
do  

do...    . 

..do  

do  

do  

do  

Caesarian  sec- 
tion. 
Low  forceps.  .  . 
Normal  
do  
do  

Primiparous.  .  . 
do  
Multiparous  .  . 
do  

..do.. 
do?.... 
do  
.    ..do...    . 

Nov.  11 
Nov.  16 
...do  

do  
do  
Primiparous.  .  . 
Multiparous  .  . 

do?.... 
do8.... 
do  
do  ..    . 

do  
do  
do  
do  

...do.... 
Nov.  19 
Nov.  22 
Nov.  27 
Nov.  30 
Dec.     6 
Dec.     8 
Dec.  13 
Dec.  14 

do     

do7  

do  

Primiparous.  .  . 
do  
Multiparous.  . 
.do  

do?.... 
do  
do  
do  

do  
Low  forceps... 
Normal  

Low  forceps.  .  . 
Normal  

do  
do  
do  

do  
do  
do  

do  
do  

xNot  birth-weight  but  weight  obtained  on  the  third  day. 
Height  obtained  after  6  days.  6Between  7  and  8  months. 

Toxemia  of  pregnancy.  "Congenital  heart. 

4Weight  obtained  after  25  hours.  'Syphilis. 


STATISTICS   OF   OBSERVATIONS. 


45 


TABLE  8 — Clinical  statistics  of  infants — Continued. 


Sub- 
ject 
No. 

Sex. 

Date  of 
birth. 

Birth. 

Term. 

Delivery. 

Birth-weight. 

Length. 

52 
53 
54 

55 
56 

57 
58 
59 
»60 
61 
62 
63 
64 
65 
66 
67 
68 
69 
70 
71 
72 

73 
74 
75 
76 
77 
78 
79 
80 
81 
82 
83 
84 
85 
86 
87 
88 
89 
90 
91 
92 
93 
294 
95 
96 
97 
98 
99 
100 
101 
102 
103 
104 
105 

F. 
M. 
M. 

M. 
M. 
M. 
F. 
F. 
M. 
M. 
M. 
F. 
F. 
F. 
M. 
M. 
M. 
M. 
M. 
M. 
M. 

M. 
M. 

M. 
M. 
F. 
M. 
F. 
M. 
F. 
M. 
M. 
F. 
M. 
F. 
M. 
F. 
M. 
M. 
F. 
F. 
M. 
M. 
F. 
F. 
F. 
F. 
M. 
M. 
M. 
M. 
F. 
M. 
M. 

1914. 
Dec.  20 
Dec.  27 
Dec.  30 
1915 
Jan.      3 
Jan.      2 
Jan.      7 
Jan.    11 
Jan.    14 
Jan.    13 
Jan.   20 
Jan.   25 
Feb.     2 
Feb.     4 
Feb.     7 
Feb.     9 
Feb.  12 
Feb.  15 
Feb.  17 
Feb.  22 
Feb.  21 
Feb.  26 

Mar.    3 
Mar.    7 
...do..  .. 
Mar.  10 
Mar.  12 
Mar.  15 
Mar.  16 
Mar.  19 
Mar.  22 
Mar.  23 
Mar.  24 
Mar.  26 
...do  

Multiparous.  . 
Primiparous.  .  . 
do  

Multiparous.  . 

Full  term... 
do  
do  

do  

Normal  

Ibs.    oz. 
8       2 

7       li 

17       7 

8      5 
7       6£ 
8     13 
7     .. 
8     14 
9      2 
7       3 
7     11 
6       3 
7      7 
5     14 
7       6 
11      .. 
5       7£ 
8      2 
8     10£ 
9       2 
7     11 

8     .. 
8       7 
6       6 
7       2 
8     10 
5       7| 
9       2 
7     10£ 
7      4 
6         \ 
8      3| 
9       1 
7     14 
7       5 
8     11 
5     13 
7       3 
7       6 
7       5| 
8       5| 
7     12* 
7       1 
6       4 
7       8 
6       7* 
6       5 
8       3 
10      4 
8       9 
6       3* 
7      4 
7      5 
7       6 

kilos. 
3.69 
3.22 
^.SS 

3.77 
3.36 
4.00 
3.18 
4.03 
4.14 
3.26 
3.49 
2.81 
3.37 
2.66 
3.35 
4.99 
2.48 
3.69 
3.93 
4.14 
3.49 

3.63 
3.83 
2.89 
3.23 
3.91 
42.48 
4.14 
3.47 
3.29 
2.74 
3.73 
4.11 
3.57 
3.32 
3.94 
2.64 
3.26 
3.35 
3.33 
3.78 
3.53 
3.20 
2.84 
3.40 
2.93 
2.86 
3.71 
4.65 
3.88 
2.82 
3.29 
3.32 
3.35 

cm. 
50 
47.5 
50 

50 
51.5 
54 
49 
52 
52 
49.5 
49.5 
47.5 
48 
49 
51 
54 
46 
50 
51 
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53 
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51 
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49.5 
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49.5 
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50.5 
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46.5 
51.5 
48 
47.5 
51.5 
54 
51.5 
47.5 
49 
51 
50.5 

do  
do  

do.    .    . 

Primiparous.  .  . 

do  

do  

Multiparous.  . 
Primiparous.  .  . 
Multiparous.  . 
do  
Primiparous.  .  . 
do  
Multiparous.  . 
do  
Primiparous.  .  . 
do  
Multiparous.  . 

do  
do  
do  
do  
do  
do  
do  
do  
do  
do  
do 

do  
do  
do  
do  
do  
do  
do  
do  
do  
do  
.do     .    . 

Primiparous.  .  . 
Multiparous.  . 

do  
.    ..do 

Low  forceps.  .  . 
Normal  

Primiparous.  .  . 
do  

.      .do.    . 

..do     .    .    . 

.    ..do. 

do     

Multiparous.  . 

.    ..do.    . 

Caesarian  sec- 
tion. 
Normal  
do  

Primiparous.  .  . 
do  

..do.. 
do3  .... 

Multiparous.  . 
do  

do  
do  

do  
do  

Primiparous.  .  . 
Multiparous.  . 
do  
Primiparous.  .  . 
Multiparous.  . 
Primiparous.  .  . 
do     

do  
do  
do  
do  
do  
do 

do?  
do....... 
do  
do  
do  
.    ..do     .    ... 

.    ..do...    . 

.    ..do  

Multiparous.  . 
do  

do  
do  

do  
do  

Mar.  30 
Mar.  31 
Apr.     2 
Apr.  20 
Apr.   19 
Apr.  22 
Apr.  24 
Apr.  27 
Apr.  28 
May     1 
May    3 
May    6 
May    7 
May  11 
May  13 
May  17 
May  19 
May  21 
May  24 
May  26 

do  
do  
Primiparous.  .  . 
Multiparous.  . 
Primiparous.  .  . 

do  
do  
do  
do  
.do.    . 

do  
do  
Low  forceps... 
Normal    ...    . 

..do       

Multiparous.  . 
.do  

..do.    .. 

do  

do  

.do  

.do  

do  

Low  forceps  .  .  . 
do  

Primiparous.  .  . 

do  

Multiparous 

do 

Normal 

Primiparous.  .  . 
do  

do  
do  

Low  forceps  .  .  . 
do  

do  

do  

Normal  
do  
do  
do  
do  
do  

Multiparous.  . 
do  
do  
Primiparous.  .  . 
Multiparous.  . 

do  
do  
do  
do  
.do.    . 

Primiparous.  .  . 

do  

do  

Multiparous.  . 

do.  ... 

do  

:Weight  obtained  after  6*  hours. 
2Negro. 


3Postpartum  eclampsia. 
4Weight  obtained  after  11  hours. 


46 


PHYSIOLOGY  OF  THE   NEW-BORN  INFANT. 


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STATISTICS    OF    OBSERVATIONS. 


47 


d 

1 

1 

1 

1 
1 
§. 

Colostrum. 

fColostrum;  sterile  water  4  min- 
\  utes  before  the  observation. 

fColostrum  ;  breast-milk  commenc- 
l  ing. 

More  breast-milk. 
Breast-milk. 

f  Sterile  water  2  minutes  before  the 
\  observation. 

f  Partly  colostrum;  sterile  water  1 
\  hour  before  the  observation. 

d 

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1 

c3 
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l 

fColostrum;  sterile  water  5  min- 
\  utes  before  the  observation. 

fColostrum;  sterile  water  9  min- 
\  utes  before  the  observation. 

fBreast-milk;  sterile  water  2  min- 
\  utes  before  the  observation. 

Breast-milk. 

The  ages  here  given  are  at  the  beginning  of  the  period  of  observation.  For  3Died  subsequently  of  congenital  syphilis  and  jaundice, 
infants  over  2  days  old,  the  age  is  given  to  the  nearest  half  day.  4Axillary  temperature. 
Calculated  from  the  weight  of  carbon  dioxide  produced  during  the  period.  5Results  with  this  subject  have  been  previously  published.  (See  Benedict 
The  preliminary  periods  for  all  days  are  omitted  in  computing  the  and  Talbot,  Am.  Journ.  Diseases  of  Children,  1914,  8,  pp.  38-39.) 
minimum  metabolism.  See  table  12,  page  95.  6Intracranial  hemorrhage  found  at  operation  on  April  12,  1914. 

" 

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PHYSIOLOGY   OF   THE   NEW-BORN   INFANT. 


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STATISTICS   OF   OBSERVATIONS. 


49 


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ents  obtained  in  the  three  preceding 
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STATISTICS   OF   OBSERVATIONS. 


51 


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3ee  table  12,  page  95. 

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3       3       3 


STATISTICS   OF   OBSERVATIONS. 


53 


Do. 

(No  food;  would  not  take  sterile 
water  about  1  hour  before  the 
observation. 

Colostrum. 
Breast-milk. 

6           6           2           d           o 
Q         P         §         Q         Q 

0 

M                          6 

dioxide  produced  during  the  period, 
all  days  are  omitted  in  computing 
See  table  12,  page  95. 

rH 

TH                   CO                   rH 

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STATISTICS   OF   OBSERVATIONS. 


63 


[Colostrum;  sterile  water  4  min- 
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Colostrum  and  breast-milk. 

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STATISTICS  OF   OBSERVATIONS. 


73 


Breast-milk  and  colostrum. 

Breast-milk. 
Colostrum. 

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STATISTICS   OP   OBSERVATIONS. 


f  Colostrum  and  breast-milk; 
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JThe  ages  here  given  are  at  the  beginning  of  the  period  of  observation.  3For  the  age  from  period  to  period,  see  table  10,  p.  81. 
For  infants  over  2  days  old  the  age  is  given  to  the  nearest  half  day.  4The  average  respiratory  quotient  obtained  during  the  entire  period  of 
Calculated  from  the  weight  of  carbon  dioxide  produced  during  the  period.  observation  has  been  used  in  computing  the  heat-production. 
The  preliminary  periods  for  all  days  are  omitted  in  computing 
the  minimum  metabolism.  See  table  12,  page  95. 

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PHYSIOLOGY   OF   THE   NEW-BORN   INFANT. 


Heat  produced 
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STATISTICS   OF   OBSERVATIONS. 


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PHYSIOLOGY   OF  THE   NEW-BORN   INFANT. 


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80  PHYSIOLOGY   OF  THE   NEW-BORN   INFANT. 

DISCUSSION  OF  RESULTS. 

The  data  we  have  accumulated  in  this  study  of  new-born  infants 
permit  a  reasonably  complete  discussion  of  several  phases  of  infant 
katabolism,  particularly  the  character  and  the  amount  of  the  katabo- 
lism  and  the  physiological  needs  of  infants  during  the  first  week  after 

birth. 

CHARACTER  OF  THE  KATABOLISM. 

Though  previous  observations  with  adults  and  animals  give  us  no  rea- 
son to  expect  any  particular  kind  of  katabolism  with  new-born  infants, 
except  that  which  may  be  due  to  the  character  of  the  food-supply  and 
possibly  to  muscular  work  as  in  severe  crying,  nevertheless  since  it  is 
commonly  believed  that  there  is  an  excess  of  glycogen  in  the  body  of 
the  new-born  infant,  it  is  necessary  to  examine  carefully  the  character 
of  the  katabolism  during  the  first  week,  if  not,  indeed,  during  the  first 
hours  of  life.  Such  a  study  will  give  evidence  as  to  the  probable  gly- 
cogen content  of  the  body,  or,  more  specifically,  the  availability  of  the 
glycogen  content  for  supplying  the  needs  of  the  body  in  the  absence 
of  the  ingestion  of  food. 

It  was  possible  to  determine  the  respiratory  exchange  of  the  infants 
by  means  of  the  respiration  apparatus,  and  from  these  data  to  calculate 
the  respiratory  quotient  for  practically  all  of  our  observations.  As  has 
already  been  pointed  out  in  our  description  of  the  technique,  the 
greatest  errors  are  liable  to  appear  in  the  determination  of  the  oxygen 
consumption,  as  this  requires  an  exact  knowledge  of  the  temperature, 
humidity,  and  barometric  pressure  inside  the  chamber.  Since  this 
error  may  be  minimized  by  measuring  the  oxygen  consumption  in 
long  periods,  it  has  been  our  custom  to  determine  the  oxygen  consump- 
tion for  the  entire  time  that  the  infant  was  inside  the  chamber,  sub- 
dividing the  observations  into  periods  upon  the  basis  of  the  carbon- 
dioxide  measurements.  In  certain  observations  these  periods  were 
made  long  enough  to  obtain  fairly  accurate  respiratory  quotients  for 
the  individual  periods.  This  is  particularly  the  case  with  the  infants 
studied  immediately  after  birth.  Our  data  are  therefore  sufficiently 
extended  to  permit  us  to  discuss  the  respiratory  quotient  of  the  new- 
born infant  during  the  first  week  of  life  and  particularly  during  the 
first  24  hours  following  birth. 

RESPIRATORY  QUOTIENT  DURING  THE  FIRST  24  HOURS  OF  LIFE. 

The  greater  part  of  our  evidence  in  regard  to  the  respiratory  quotient 
during  the  first  24  hours  of  life  was  obtained  in  those  observations 
which  were  specifically  designed  to  study  this  question,  namely,  those 
in  which  the  infants  were  observed  almost  immediately  after  birth. 
The  periods  were  for  the  most  part  1  hour  long  and  therefore  may  rea- 
sonably be  expected  to  give  satisfactory  determinations  of  the  oxygen 
consumption.  The  results  are  given  in  abstract  in  table  10. 


CHARACTEE  OF  THE  KATABOLISM. 


81 


TABLE  10. — Respiratory  quotients  of  infants  during  early  hours  after  birth. 


Relative 

Relative 

Sub- 
ject 
No. 

Sex. 

Age  at 
begin- 
ning of 
period. 

Respi- 
ratory 
quo- 
tient.1 

Car- 
bon 
diox- 
ide per 
hour. 

activity2 
estimated 
from  kymo- 
graph records. 

Sub- 
ject 
No. 

Sex. 

Age  at 
begin- 
ning of 
period. 

Respi- 
ratory 
quo- 
tient.1 

Car- 
bon 
diox- 
ide per 
hour. 

activity2 
estimated 
from  Kymo- 
graph records. 

Obs. 

Obs. 

Obs. 

Obs. 

I. 

II. 

I. 

II. 

h.   m. 

Qvn. 

h.   m. 

gm. 

80 

M. 

2     .  . 

0.75 

2.14 

B  ' 

B 

95 

F. 

4     15 

0.83 

1.71 

B 

B 

3     .  . 

.78 

1.76 

A 

A 

5     15 

.70 

1.41 

A 

A 

4      .  . 

.90 

3.99 

D 

C 

6     15 

.84 

1.58 

B 

B 

6      .. 

3.78 

2.39 

C 

B 

7     15 

[.93] 

2.09 

E 

D 

82 

M. 

3      .. 

.76 

1.28 

A 

A 

96 

F. 

1     15 

.93 

.87 

F 

D 

4     15 

.78 

1.60 

B 

B 

2     15 

.85 

.75 

D 

C 

5     15 

.83 

1.75 

B 

B 

3     30 

.91 

.65 

A 

A 

6     15 

.80 

1.77 

C 

B 

4     30 

.89 

.95 

C 

B 

83 

M. 

2     30 

.80 

2.06 

A 

A 

5     30 

.80 

.75 

A 

A 

3     30 

.90 

2.21 

A 

A 

6     30 

.86 

.88 

B 

B 

4     30 

.83 

2.22 

B 

B 

7     30 

.86 

.09 

E 

E 

5     30 

.83 

2.20 

C 

C 

97 

F. 

2     .  . 

.85 

.82 

F 

F 

6     30 

.85 

2.24 

B 

B 

3     .. 

.84 

.75 

E 

E 

7     30 

.79 

2.39 

D 

D 

4      .  . 

.82 

.58 

A 

A 

8     30 

[.99] 

3.55 

E 

E 

5     .. 

.87 

.61 

B 

B 

84 

F. 

2      .  . 

.76 

1.82 

B 

A 

6     .  . 

.87 

.65 

D 

E 

3      .. 

.83 

1.81 

A 

A 

7     .. 

.86 

.84 

C 

D 

4      .  . 

.80 

2.26 

D 

C 

8     .. 

.86 

.80 

C 

C 

5      .  . 

.86 

3.09 

F 

D 

98 

F. 

2      .  . 

0.77 

.33 

D 

C 

6      .. 

.83 

2.70 

E 

C 

3     .. 

.90 

.93 

F 

D 

7     .. 

.75 

2.02 

C 

B 

4      .  . 

.90 

.22 

E 

E 

8     .. 

.77 

2.04 

C 

B 

5     .. 

.74 

.50 

C 

B 

87 

M. 

1     30 

.79 

2.06 

A 

A 

6     .. 

.74 

.37 

B 

A 

2     45 

[1.05] 

2.71 

D 

C 

7     .. 

.79 

.38 

A 

A 

3     30 

[-90] 

3.78 

F 

D 

8     15 

.85 

.50 

B 

A 

4     45 

.81 

2.42 

B 

B 

99 

M. 

1     30 

.79 

2.09 

B 

B 

5     45 

.76 

2.18 

A 

A 

2     30 

.83 

1.78 

A 

A 

6     45 

.84 

2.27 

C 

B 

3     30 

.93 

3.09 

D 

C 

7     45 

[-96] 

3.70 

E 

D 

4     30 

.90 

2.33 

C 

B 

93 

M. 

1 

.83 

2.69 

F 

F 

6     .  . 

.83 

2.00 

A 

A 

2      .. 

.77 

1.86 

D 

C 

7     .. 

.89 

2.81 

D 

D 

3      .. 

.79 

2.01 

C 

D 

7    45 

.87 

3.25 

E 

E 

4     .. 

.87 

2.69 

E 

E 

100 

M. 

1     15 

.90 

3.47 

D 

E 

5     .. 

.76 

1.89 

B 

A 

2     15 

.98 

3.43 

D 

F 

6     .  . 

.77 

1.89 

A 

A 

3     15 

1.00 

4.36 

E 

G 

7     .  . 

.86 

2.07 

B 

B 

4     15 

.85 

2.86 

C 

D 

94 

M. 

1     15 

.76 

2.09 

C 

D 

5     15 

.87 

2.96 

A 

B 

2     15 

.87 

2.16 

D 

D 

6     15 

.91 

2.81 

A 

A 

3     15 

.81 

1.89 

A 

A 

7     15 

.82 

3.12 

B 

C 

4     15 

.75 

2.12 

C 

B 

101 

M. 

1     15 

.89 

2.34 

C 

C 

5     15 

[-96] 

3.24 

F 

E 

2     15 

1.00 

2.69 

F 

E 

6     15 

.80 

2.29 

C 

C 

3     15 

.94 

2.73 

E 

E 

7     15 

.79 

2.07 

B 

B 

4     15 

.82 

1.90 

B 

B 

95 

F. 

1     15 

.89 

1.90 

D 

C 

5     15 

.81 

1.87 

A 

A 

2     15 

.80 

1.54 

C 

B 

6     15 

.88 

2.27 

D 

D 

3     15 

.84 

1.65 

B 

B 

7     15 

.86 

2.29 

D 

D 

Duration  of  periods  about  1  hour  in  practically  all  cases. 

JThe  designations  here  used  indicate  only  that  the  activity  in  one  period  is  greater  or  less  than  in 

the  other  periods,  the  letter  A  being  applied  to  the  period  of  least  activity  in  each  case. 

The  designations  are  not  comparable  for  the  different  subjects. 
8This  quotient  was  obtained  following  an  interval  in  which  the    cover   of    the    chamber   was 

removed  to  give  the  baby  a  small  amount  of  sterile  water  and  after  a  second  preliminary 

period. 


82 


PHYSIOLOGY   OF   THE    NEW-BORN   INFANT. 


TABLE  10. — Respiratory  quotients  of  infants  during  early  hours  after  birth — Continued. 


Relative 

Relative 

Sub- 
ject 
No. 

Sex. 

Age  at 
begin- 
ning of 
period. 

Respi- 
ratory 
quo- 
tient.1 

Car- 
bon 
diox- 
ide per 
hour. 

activity2 
estimated 
from  kymo- 
graph records. 

Sub- 
ject 
No. 

Sex. 

Age  at 
begin- 
ning of 
period. 

Respi- 
ratory 
quo- 
tient.1 

Car- 
bon 
diox- 
ide per 
hour. 

activity2 
estimated 
from  kymo- 
graph records. 

Obs. 

Obs. 

Obs. 

Obs. 

I. 

II. 

I. 

II. 

h.   m. 

gm. 

h.   m. 

gm. 

102 

M. 

2     15 

0.83 

1.76 

D 

C 

104 

M. 

1     45 

0.92 

1.90 

D 

C 

3     15 

.80 

1.55 

C 

C 

2     45 

.85 

1.55 

B 

A 

4     15 

.82 

1.43 

A 

A 

3     45 

.96 

1.68 

A 

A 

5     15 

.78 

1.49 

B 

B 

5     .. 

.89 

1.65 

C 

B 

6     15 

.88 

2.19 

E 

D 

6     .. 

.88 

2.58 

E 

D 

7     30 

.80 

1.89 

D 

C 

7     .. 

.82 

1.95 

C 

C 

8     30 

.81 

2.28 

F 

E 

105 

M. 

3     15 

.83 

1.85 

A 

A 

103 

F. 

1     15 

.89 

2.25 

A 

A 

4     30 

.89 

2.12 

E 

D 

2     15 

.78 

1.87 

A 

B 

5     30 

.89 

2.33 

D 

E 

3     15 

.91 

2.63 

D 

D 

6     30 

.82 

1.90 

A 

A 

4     15 

.85 

2.96 

E 

D 

7     30 

.81 

2.02 

C 

B 

5     15 

.81 

2.15 

B 

C 

8     30 

.82 

2.41 

D 

E 

6     15 

.88 

2.99 

D 

D 

9     30 

.82 

2.04 

C 

C 

7     15 

.85 

2.82 

C 

D 

1Duration  of  periods  about  1  hour  in  practically  all  cases. 

2The  designations  here  used  indicate  only  that  the  activity  in  one  period  is  greater  or  less  than  in 

the  other  periods,  the  letter  A  being  applied  to  the  period  of  least  activity  in  each  case. 

The  designations  are  not  comparable  for  the  different  subjects. 

When  we  examine  the  individual  quotients  for  each  day,  we  find 
that  at  times  there  are  great  fluctuations,  as,  for  instance,  in  the  case  of 
subject  83,  in  which  there  was  an  increase  in  the  last  period  from  0.79 
to  0.99.  Since  the  infant  had  had  no  previous  nourishment  and  was 
without  food  during  the  whole  time  that  it  lay  in  the  respiration 
chamber,  it  is  of  course  inconceivable  that  after  8J  hours  of  fasting 
subsequent  to  birth  there  should  have  been  this  qualitative  alteration 
to  a  metabolism  which  would  be  indicative  of  pure  carbohydrate  com- 
bustion. On  several  other  days  similar  abnormal  respiratory  quotients 
are  found,  these  being  indicated  in  the  table  by  brackets.  These 
brackets  are  not  used  to  differentiate  sharply  between  the  correct  and 
incorrect  quotients,  but  merely  to  point  out  the  most  strikingly  defective 
quotients. 

There  may  be  two  reasons  for  these  defective  quotients.  In  the 
first  place,  they  may  be  due  to  excessive  carbon-dioxide  excretion, 
unaccompanied  by  a  corresponding  increase  in  the  oxygen  absorption, 
or  they  may  be  due  to  a  defect  in  the  measurement  of  the  oxygen, 
particularly  of  the  residual  oxygen  inside  the  chamber.  If  we  examine 
the  values  given  in  this  table  for  the  total  carbon-dioxide  production, 
we  find  that  at  times  there  are  very  great  increases.  Thus,  with 
infant  No.  80,  there  was  an  increase  of  over  100  per  cent  in  the  carbon- 
dioxide  production  from  the  second  to  the  third  period  of  the  observa- 
tion, this  being  accompanied  by  an  increase  of  0.12  in  the  respiratory 


CHARACTER  OF  THE  KATABOLISM.  83 

quotient.  With  practically  all  of  the  quotients  which  are  inclosed  in 
brackets  we  find  very  great  increases  in  the  carbon-dioxide  production 
over  that  of  the  preceding  period;  hence  we  may  ascribe  at  least  a 
portion  of  this  change  in  the  quotient  to  an  excess  carbon-dioxide 
excretion.  It  is  not  impossible  that  a  certain  amount  of  the  carbon 
dioxide  thus  excreted  may  be  due  to  actual  over-ventilation  of  the 
lungs  of  the  infant,  produced  by  excessive  crying;  this  can  not,  how- 
ever, account  for  the  entire  increase. 

For  a  partial  explanation  of  these  variations  in  the  carbon-dioxide 
production,  we  may  with  profit  examine  the  kymograph  records  accom- 
panying each  period.  It  is  impracticable  to  publish  all  of  the  records 
obtained  in  this  series  of  observations;  accordingly  two  skilled  observers 
have  examined  them  independently  and  have  indicated  the  relative 
activity  by  ascribing  a  letter  to  each  individual  period.  This  classi- 
fication is  not  intended  as  a  comparison  of  the  activity  of  one  infant 
with  another,  nor  do  the  letters  designate  arbitrary  degrees  of  muscular 
repose.  They  apply  only  to  the  activity  of  each  infant  by  itself  and 
show  the  muscular  repose  of  the  individual  periods  as  related  to  that 
of  the  other  periods,  A  being  used  to  designate  the  greatest  degree  of 
muscular  repose.  If  there  are  two  periods  in  an  observation  when  the 
muscular  repose  is  of  exactly  the  same  degree,  they  are  given  the  same 
letter.  (See  infant  No.  82.)  The  estimations  made  by  Observer  I 
and  Observer  II  never  differ  more  than  one  unit  in  classification  and 
usually  they  are  identical.  It  will  be  seen  that  in  practically  all  of  the 
instances  in  which  abnormally  high  quotients  were  found,  there  was 
a  great  increase  in  the  activity  as  shown  by  the  kymograph  record. 
While  a  variation  in  the  degree  of  muscular  repose  is  not  always 
accompanied  by  a  variation  in  the  respiratory  quotient,  nevertheless 
this  is  true  in  the  majority  of  cases. 

In  view  of  these  considerations,  we  must  accept  with  reserve  the 
respiratory  quotients  which  do  not  lie  within  reasonable  limits  of  the 
average  quotient  for  the  day.  If  the  infant  organism  were  surcharged 
with  glycogen  we  would  normally  expect  to  find  a  high  respiratory 
quotient  shortly  after  birth,  with  a  gradual  decrease  throughout  the 
day.  A  critical  examination  of  all  of  the  values  in  table  10  shows 
a  distinct,  though  slight,  tendency  for  the  quotient  to  fall  off  during 
the  day;  on  the  other  hand,  the  initial  quotients  are  not  extremely  high, 
being  for  the  most  part  considerably  less  than  0.90.  We  may  there- 
fore properly  conclude  that  while  the  quotients  have  a  tendency  to 
decrease  as  the  period  of  inanition  lengthens,  since  the  quotients  are 
rarely  as  high  as  0.90,  even  when  obvious  technical  errors  are  eliminated, 
we  can  not  infer  that  the  katabolism  is  chiefly  that  of  carbohydrate 
during  the  observation  period. 

According  to  the  table  of  Zuntz  and  Schumburg,  a  non-protein 
respirato^  quotient  of  0.90  corresponds  to  a  combustion  in  which 
66  per  cent  of  the  total  energy  is  derived  from  carbohydrate  and  34 


84  PHYSIOLOGY   OF   THE   NEW-BORN   INFANT. 

per  cent  from  fat.  While  with  these  infants  we  have  not  been  able 
to  secure  a  non-protein  respiratory  quotient,  we  may  safely  disregard 
this  fact  and  assume  that  a  quotient  of  0.90  with  these  infants  cor- 
responds to  a  katabolism  in  which  approximately  two-thirds  of  the 
maintenance  metabolism  is  derived  from  carbohydrate. 

To  obtain  the  average  respiratory  quotient  for  these  infants  on  the 
first  day  of  life,  we  may  best  examine  the  values  given  in  table  11, 
in  which  all  of  the  respiratory  quotients  on  the  first  day  have  been 
brought  together  and  averaged.  We  find  that  the  average  respiratory 
quotient  for  74  infants  on  the  first  day  of  life  was  0.80,  a  value  materi- 
ally lower  than  the  quotient  of  0.90  occasionally  appearing  in  the  first 
few  hours  of  life.  This  value  of  0.80  represents  a  fasting  value  not 
widely  different  from  that  observed  during  the  first  24  hours  with  fasting 
man,  a  previous  publication  from  this  laboratory  showing  that  the  aver- 
age respiratory  quotient  in  14  experiments  with  10  men  was  0.79  on  the 
first  day.1 

Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  77,  1907,  p.  451. 


CHARACTER    OP   THE    KATABOLISM. 


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88 


PHYSIOLOGY   OF   THE   NEW-BORN   INFANT. 


Some  of  the  infants  obtained  a  certain  amount  of  colostrum  prior 
to  the  measurement  of  the  metabolism;  they  were  therefore  not  in 
all  cases  in  the  post-absorptive  condition  when  the  metabolism  was 
measured.  Most  of  the  infants,  however,  were  in  the  post-absorptive 
condition  during  the  observations  and  the  average  value  obtained  for 
the  respiratory  quotient,  i.  e.,  0.80,  may  very  properly  be  compared 
with  the  average  respiratory  quotient  of  0.79  which  was  previously  cited 
for  10  men  on  the  first  day  of  their  fast.  This  comparison  of  itself 
would  therefore  lead  one  to  conclude  that  there  was  not  an  excessive 
deposit  of  glycogen  in  the  bodies  of  new-born  children,  for  according  to 
the  table  of  Zuntz  and  Schumburg,  a  respiratory  quotient  of  0.79  corre- 
sponds to  a  metabolism  in  which  approximately  one-third  of  the  energy 
comes  from  carbohydrate  and  two-thirds  from  fat. 


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Age  in  Hours 
FIG.  1. — Respiratory  quotients  of  infants  found  at  various  times  during  the  first  24  hours. 

The  trend  of  the  respiratory  quotient  during  the  first  24  hours  after 
birth  may  perhaps  best  be  shown  graphical^.  We  have  therefore 
plotted  from  table  10  all  of  the  individual  respiratory  quotients  obtained 
during  the  first  day,  with  the  exception  of  the  bracketed  values,  and 
have  supplemented  these  with  the  average  values  from  table  11  for  the 
infants  whose  respiratory  exchange  was  not  studied  in  short  periods  in 
the  first  24  hours.  The  values  on  this  chart  (see  fig.  1)  show  that 
during  the  first  24  hours  of  life  there  was  a  slight,  though  definitely 
observable,  decrease  in  the  respiratory  quotient  as  time  progressed. 
Although  this  was  not  sufficiently  characteristic  to  justify  its  represen- 
tation by  a  curve,  when  we  compare  the  quotients  above  and  below 
0.80,  we  find  that  up  to  the  eighth  hour  the  greater  number  lie  above 
0.80,  while  subsequent  to  the  tenth  hour  the  larger  proportion  lie  below 
this  value. 


CHARACTER   OF   THE    KATABOLISM.  89 

RESPIRATORY  QUOTIENT  DURING  THE  FIRST  WEEK  OF  LIFE. 

Table  11  also  shows  the  respiratory  quotients  obtained  for  each  day 
up  to  the  eighth  day  inclusive,  the  interval  between  successive  daily  quo- 
tients being  approximately  24  hours.  The  time  when  the  breast-milk 
appeared  is  designated  by  an  asterisk  (*)  and  when  the  milk  was  suffi- 
cient in  amount  by  the  designation  (J).  Evidence  that  the  infant  was 
clearly  gaining  weight  was  the  criterion  used  in  placing  the  designation 
(t) .  In  the  case  of  certain  infants  who  were  3  or  more  days  old  when 
the  first  observations  were  made,  no  designations  have  been  placed  on 
the  respiratory  quotients,  since  apparently  the  breast-milk  was  already 
established.  Furthermore,  when  there  was  an  interval  of  more  than 
36  hours  between  observations,  either  of  the  designations  may  have 
been  omitted.  When  there  was  no  gain  in  weight,  even  if  breast-milk 
was  recorded,  it  evidently  was  not  sufficient;  the  designation  (J)  was 
therefore  omitted.  All  weights  are  without  clothing. 

If  we  study  the  variations  in  the  respiratory  quotient  found  with  the 
new-born  infants  during  the  first  week  of  life  as  shown  in  table  11, 
we  note  a  distinct  tendency  for  the  quotient  to  decrease  after  the  first 
day,  reaching  the  lowest  average  of  0.73  on  the  third  day.  Thereafter 
there  was  a  tendency  for  the  respiratory  quotient  to  increase  and  on  the 
last  3  days  the  average  was  not  far  from  0.81.  The  average  value 
found  with  74  infants  on  the  first  day  was  0.80;  with  64  infants  on  the 
second  day,  0.74;  with  62  infants  on  the  third  day,  0.73;  with  51  infants 
on  the  fourth  day,  0.75;  with  41  infants  on  the  fifth  day,  0.79;  with  22 
infants  on  the  sixth  day,  0.82;  with  15  infants  on  the  seventh  day,  0.81 ; 
and  with  9  infants  on  the  eighth  day,  0.80.  It  is  quite  obvious  that 
some  factor  entering  into  the  nourishment  of  the  infant  produced  a 
change  in  the  metabolism  which  raised  the  average  respiratory  quotient 
from  a  minimum  of  0.73  on  the  third  day  of  life  to  0.81  at  the  end  of  the 
first  week. 

According  to  the  table  of  Zuntz  and  Schumburg,  if  we  assume  that 
these  are  non-protein  respiratory  quotients,  0.73  would  correspond  to 
a  metabolism  in  which  somewhat  less  than  10  per  cent  of  the  energy 
was  derived  from  carbohydrate  and  the  remainder  from  fat,  while  a 
quotient  of  0.81  would  correspond  to  a  metabolism  in  which  one-third 
of  the  energy  was  the  result  of  a  carbohydrate  combustion  and  two- 
thirds  was  derived  from  a  fat  combustion.  It  is  thus  obvious  that  the 
infant  between  the  third  and  seventh  days  secured  a  supply  of  carbo- 
hydrate which  was  not  drawn  from  the  body-material.  This  could  be 
derived  only  from  the  nourishment  taken,  usually  in  the  mother's  milk. 

The  profound  influence  of  the  mother's  milk  upon  the  character  of 
the  katabolism  is  shown  by  the  fact  that  the  time  when  the  milk  began 
to  appear  in  the  mother's  breasts,  as  indicated  by  the  asterisk  (*), 
almost  invariably  coincides  with  the  increase  in  the  respiratory  quo- 
tient. On  the  first  day  of  life  the  infant  is  subsisting  upon  the  moder- 


90  PHYSIOLOGY   OF   THE   NEW-BORN   INFANT. 

ate  amount  of  glycogen  in  the  body  at  birth.  On  the  second,  third, 
and  fourth  days  the  colostrum  is  entirely  insufficient  to  supply  the 
needed  energy;  on  the  fifth  day  the  milk  flow  is  usually  estab- 
lished and  subsequently  the  respiratory  quotient  is  not  far  from  0.81, 
indicating  a  katabolism  in  which  somewhat  over  one-third  of  the 
energy  is  derived  from  carbohydrate.  This  quotient  is  not  far  from  that 
found  with  normal  individuals.  Thus,  in  the  study  made  by  Benedict, 
Emmes,  Roth,  and  Smith,1  in  which  157  individuals  (89  men  and  68 
women)  subsisting  upon  a  mixed  diet  were  studied,  the  post-absorptive 
katabolism  showed  a  respiratory  quotient  of  0.81.  Comparing  this 
average  value  with  the  respiratory  quotients  found  with  the  new-born 
infants,  we  may  properly  infer  that  the  infant  at  birth  has  not  an  exces- 
sive supply  of  glycogen  in  the  tissues.  We  may  further  conclude  that 
the  glycogen  supply  is  somewhat  rapidly  exhausted  on  the  first  day  and 
it  is  not  until  the  supply  of  milk  from  the  mother's  breasts  is  established 
that  we  find  a  respiratory  quotient  indicating  a  considerable  combustion 
of  carbohydrate. 

Further  light  is  thrown  upon  this  subject  by  a  consideration  of  the 
changes  in  body-weight  during  the  first  week.  While  it  is  practically 
a  routine  in  all  hospitals  to  record  the  birth-weight  of  infants,  it  is 
a  well-known  fact  that  in  many  instances  the  record  may  represent 
the  weight  either  before  or  after  the  meconium  is  passed,  and  that  the 
true  physiological  weight  is  not  known.  It  is  rarely  that  weights  are 
obtained  from  day  to  day,  so  that  comparisons  can  be  made  and  the 
curve  studied.  As  was  stated  in  a  previous  section,  there  is  at  first  a 
distinct  normal  loss  in  body-weight  with  a  subsequent  rise;  our  obser- 
vations, the  results  of  which  are  given  in  table  11,  have  in  consequence 
a  peculiar  significance  in  this  connection. 

The  average  body-weight  for  the  first  7  days  of  life  was  as  follows: 
On  the  first  day,  with  74  subjects,  3.48  kg.;  on  the  second  day,  with 
64  subjects,  3.41  kg.;  on  the  third  day,  with  62  subjects,  3.32  kg.; 
on  the  fourth  day,  with  51  subjects,  3.34  kg.;  on  the  fifth  day,  with 
41  subjects,  3.43  kg.;  on  the  sixth  day,  with  22  subjects,  3.51  kg.; 
and  on  the  seventh  day,  with  15  subjects,  3.54  kg.  These  figures  are 
not  wholly  comparable,  as  the  weights  were  not  obtained  for  the  same 
individuals  during  the  whole  period.  Computations  were  made, 
however,  of  the  body-weight  of  44  infants  for  both  the  first  and  second 
days;  these  show  that  the  body-weight  for  the  first  day  was  3.61  kg. 
and  for  the  second  day,  3.44  kg.  There  was  therefore  a  loss  of  weight 
during  the  first  day  of  170  grams.  It  is  also  clear  that  there  was  a 
further  distinct  loss  on  the  second  and  third  days,  which  was  followed 
by  an  increase  in  the  later  days.  It  should  be  stated  that  during  the 
first  few  days  the  small  amount  of  food  taken  would  have  relatively  but 
little  effect  upon  the  body-weight,  although  the  sterile  water,  which  was 

Benedict,  Emmes,  Roth,  and  Smith,  Journ.  Biol.  Chem.,  1914, 18,  p.  139. 


CHARACTER  OF  THE  KATABOLISM. 


91 


frequently  given,  would  naturally  tend  to  increase  the  weight  some- 
what. On  the  other  hand,  the  170  grams  of  body- weight  lost  on  the 
first  day  can  not  in  any  way  be  considered  as  being  a  loss  of  either 
flesh  or  fat,  but,  as  was  pointed  out  in  a  preceding  section,  was  doubtless 
due  in  large  part  to  a  loss  of  water  from  the  body. 

It  was  noted  that  the  establishment  of  the  flow  of  milk  was,  as  a  rule, 
coincident  with  an  increase  in  the  respiratory  quotient.  Here  again  we 
find  in  considering  the  records  of  the  body-weight  that  this  factor  also 
tends  to  increase  at  the  time  that  the  milk-flow  is  established.  In 
general,  therefore,  after  the  first  day  the  infant  loses  weight  while  the 
food-supply  is  insufficient,  particularly  in  carbohydrate,  and  increases 
in  weight  when  the  milk-supply  is  established. 

INFLUENCE  OF  BODY-WEIGHT  UPON  THE  RESPIRATORY  QUOTIENT. 

Since  it  was  possible  that  the  store  of  glycogen  in  the  body  of  the 
infant  might  vary  considerably  with  variations  in  the  size  and  nourish- 
ment, the  respiratory  quotients  were  compared  with  the  body-weights 
of  the  infants.  This  comparison  is  shown  in  figure  2,  in  which  the 
actual  body-weights  of  the  infants  during  the  first  24  hours  are  plotted 


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*ff    • 

•.• 

•. 

*   .• 

. 

•' 

• 

* 

30       2.50       2.70       2.90       3.10       3.30       3.50       3.70       3.90       4.10       4.30       4.50       4.70      4.90       5. 
Body  Weight.  Kilos. 

G.  2.  —  Respiratory  quotient  of  infants  in  first  24  hours  referred  to  total  body-weight. 

against  the  respiratory  quotients  obtained  for  the  same  period.  A 
careful  examination  of  the  chart  shows  no  tendency  toward  a  variation 
in  the  average  quotient  as  the  weight  varies.  We  must  therefore  infer 
that  the  respiratory  quotient  is  independent  of  the  weight. 


I.UU 

• 

. 

. 

• 

• 

§ 

1 

• 

• 

.     * 

- 

. 

S 

*     TQ 

*      ' 

• 

•V 

'•" 

'   . 

'• 

• 

• 

.60 

' 

• 

.082       .085 


.052       .055      .058       .0.61        .064-       .067       .070       .073       .076       .079 

Body  Weight  per  Cm.  of  Length.  Kilo. 

FIG.  3. — Respiratory  quotient  of  infants  in  first  24  hours  referred  to  body-weight  per 

unit  of  length  of  infant. 


.094 


92  PHYSIOLOGY   OF  THE   NEW-BORN   INFANT. 

Since,  however,  infants  of  approximately  the  same  weight  but  of 
varying  length  may  differ  in  the  degree  of  nourishment,  the  relationship 
between  the  weight  and  the  length  of  the  infants  may  be  of  significance 
hi  this  connection;  the  weight  per  unit  of  length  may  thus  be  a  better 
basis  for  comparison  than  the  actual  weight.  The  values  have  there- 
fore been  compared  on  this  basis  in  figure  3,  in  which  the  respiratory 
quotients  have  been  plotted  against  the  weight  per  unit  of  length. 
Using  the  average  respiratory  quotient  of  0.80  as  a  base-line,  we  find 
no  distinct  tendency  toward  a  grouping  of  the  values.  Such  differences 
as  may  be  apparent  are  not  sufficiently  striking  to  allow  us  to  make  any 
other  deduction  than  that  the  respiratory  quotient  appears  to  be  abso- 
lutely independent  of  the  weight  and  the  state  of  nutrition.  Unfortu- 
nately our  hospital  and  other  data  do  not  provide  definite  information 
regarding  the  degree  of  nutrition  of  the  mothers.  No  relationship  can 
therefore  be  established  between  the  nature  of  the  katabolism  of  the 
new-born  inf ant  in  the  first  few  hours  after  birth  and  the  state  of  nutri- 
tion of  the  mother. 

GENERAL  CONCLUSIONS  AS  TO  CHARACTER  OF  KATABOLISM 
OF  NEW-BORN  INFANTS. 

From  the  results  obtained  in  our  experiments  we  are  unable  to  verify 
Hasselbalch's  conclusion  that  the  metabolism  of  the  new-born  infant 
in  the  first  few  hours  is  chiefly  of  carbohydrate  material.  It  is  true 
that  in  practically  none  of  our  observations  were  we  able  to  secure  data 
so  soon  after  birth  as  did  Hasselbalch.  Thus,  while  he  frequently 
records  observations  beginning  30  to  45  minutes  after  birth  and,  indeed, 
in  one  instance  15  minutes  after  birth,  our  values  were  rarely  obtained 
in  observations  less  than  an  hour  after  birth,  and  for  the  most  part 
they  were  2  or  more  hours  after  birth.  On  the  other  hand,  the  time 
relations  in  our  observations  are  fully  comparable  to  the  fragmentary 
data  published  by  Bailey  and  Murlin,  since  in  only  two  of  their  cases 
were  observations  made  as  early  as  6  hours  after  birth,  and  there  was 
but  one  period  in  each  case. 

If  we  examine  the  data  published  by  Hasselbalch,  particularly  the 
values  given  in  table  2  (see  page  21),  we  find  that  a  great  decrease 
in  the  respiratory  quotient  is  accompanied  by  a  very  large  decrease  in 
the  total  katabolism  as  indicated  by  the  carbon-dioxide  production. 
Thus  in  his  observation  No.  17  the  carbon-dioxide  production  per  kilo- 
gram per  hour  was  344  c.c.  and  the  respiratory  quotient  was  0.933, 
while  the  next  period  showed  a  carbon-dioxide  production  per  kilogram 
per  hour  of  only  275  c.c.  and  a  respiratory  quotient  of  0.854.  A  similar 
relationship  between  the  variations  in  the  metabolism  as  indicated  by 


CHARACTER  OF  THE  KATABOLISM.  93 

the  carbon-dioxide  production  and  the  respiratory  quotient  is  shown  in 
observations  Nos.  13-14  and  19-20. 

It  will  be  remembered  that  in  our  consideration  of  the  values  in  table 
10  (see  page  81),  a  like  increase  in  the  metabolism  was  found  to  accom- 
pany the  abnormal  increase  in  the  respiratory  quotient  and  that  the 
conclusion  was  drawn  that  this  increase  was  in  part  due  to  the  muscular 
activity  of  the  infant,  and  specifically  to  the  excess  carbon-dioxide 
produced  in  crying.  The  notes  accompanying  Hasselbalch's  protocols 
specify  that  the  infant  was  not  crying;  nevertheless  we  know  too  little  at 
present  regarding  the  ventilation  of  the  lungs  of  new-born  infants  not  to 
assume  that  there  may  certainly  have  been  a  distinctly  excessive  ventila- 
tion, with  an  accompanying  increase  in  the  carbon-dioxide  excretion. 
We  have  here,  then,  an  actual  increase  in  the  katabolism  of  considerable 
magnitude,  with  the  high  probability  of  there  being  somewhat  more  car- 
bon dioxide  produced  than  oxygen  consumed,  the  difference  being  suffi- 
cient to  cause  a  corresponding  variation  in  the  respiratory  quotient. 

The  fact  that  in  a  large  number  of  our  observations  of  long  duration 
these  abnormally  high  quotients  appear  not  only  in  the  first  hours,  but, 
later,  lends  considerable  strength  to  this  supposition.  We  are  inclined 
to  believe,  therefore,  that  Hasselbalch's  conclusion  that  the  higher 
respiratory  quotients  are  obtained  in  those  observations  which  are 
nearest  to  the  birth  is  due  not  to  the  larger  proportion  of  the  glycogen 
taking  part  in  the  combustion,  but  to  an  increase  in  the  carbon-dioxide 
excretion,  owing  to  a  disturbance  in  the  mechanics  of  respiration. 

On  the  first  day  of  life  there  is  a  gradual  decrease  in  the  respiratory 
quotient  which  is  fully  comparable  to  that  experienced  with  any  fasting 
organism  in  which  the  initial  supply  of  glycogen  is  fairly  liberal.  On 
the  other  hand,  the  quotients  found  shortly  after  birth  and  the  level 
to  which  they  fall  on  the  first  day  are  not  such  as  to  justify  the  conclu- 
sion that  there  is  an  excessive  glycogen  storage  in  the  body  of  the  new- 
born infant.  On  the  second  and  subsequent  days  the-  respiratory 
quotients  decrease,  indicating  a  somewhat  rapid  depletion  of  glycogen 
until  the  quotient  of  0.73  is  reached,  this  being  similar  to  the  metabo- 
lism of  fasting  animals.  When  the  milk-flow  is  fully  established,  and 
the  body  is  in  consequence  supplied  more  liberally  with  carbohydrate 
material,  the  average  respiratory  quotient  increases  until  at  the  end 
of  the  first  week  it  is  0.81. 

No  obvious  relationship  between  the  respiratory  quotient  and  the 
size  and  condition  of  nourishment  can  be  found  from  the  data  obtained. 
As  information  is  lacking  in  regard  to  the  degree  of  nourishment  of  the 
mothers,  no  study  can  be  made  of  the  relationship  between  the  respira- 
tory quotient  and  this  factor. 


94  PHYSIOLOGY   OF  THE   NEW-BORN   INFANT. 

BASAL  KATABOLISM. 

Direct  measurements  of  the  heat-production  are  only  possible  with 
extremely  complicated  and  expensive  calorimetric  devices.  Thus 
far  no  one  has  successfully  completed  such  measurements  with  infants 
save  Rowland.1  As  it  was  impracticable  to  make  direct  measure- 
ments of  the  heat-output  in  our  study  of  the  metabolism  of  new-born 
infants,  we  were  obliged  to  content  ourselves  with  the  indirect  method 
of  computing  the  energy  from  the  carbon-dioxide  elimination  and 
the  oxygen  consumption.  Fortunately  the  interesting  research  of 
Rowland  has  shown  that  this  method  of  determining  the  energy  out- 
put gives  results  of  a  high  degree  of  accuracy.  On  the  other  hand, 
it  is  impossible  to  compare  the  results  obtained  with  an  infant  in 
half-hour  or  hour  periods  at  different  times  of  the  day  unless  there  was 
like  extraneous  muscular  activity  in  the  periods  compared.  It  is 
much  less  possible  to  compare  the  results  obtained  with  different  infants 
without  an  assurance  of  complete  muscular  repose  during  the  time 
of  the  observations.  From  the  beginning  of  our  research  we  have  laid 
emphasis  upon  graphic  records  of  the  degree  of  muscular  repose,  and  we 
are  glad  to  note  that  this  is  now  bearing  fruit  in  that  practically  all 
experimenters  are  to-day  of  one  mind  regarding  the  absolute  necessity 
of  using  periods  of  minimum  activity  for  comparison. 

Even  in  so  extended  a  series  of  observations  as  is  reported  here,  we 
were  not  able  with  all  of  the  infants  to  secure  periods  of  absolutely 
minimum  muscular  activity.  A  critical  examination  of  all  the  kymo- 
graph records  was  made  independently  by  two  skilled  observers  and 
periods  of  practically  minimum  activity  were  selected  wherever  it  was 
possible.  In  the  selection  of  these  periods,  however,  actual  minimum 
heat  values  were  sought;  a  careful  inspection  was  therefore  made  of 
the  heat-production  as  computed  from  the  carbon  dioxide  observed. 
Minimum  values  were  secured  for  94  out  of  the  105  infants.  These 
results  have  been  averaged  and  are  given  in  table  12.  It  was  rarely 
necessary  to  make  use  of  a  minimum  value  obtained  from  but  one  period 
in  the  series  of  observations  with  an  infant.  These  periods  of  minimum 
activity  and  heat-production  may  be  found  with  comparative  ease  by 
referring  to  the  statistical  table  (see  pages  46  to  79). 

lowland,  Proc.  Soc.  Exp.  Biol.  and  Med.,  1911,  8,  p.  63;  Hoppe-Seyler's  Zeitschr.  f.  Physiol. 
Chem.,  1911,  74,  p.  1;  Trans.  15th  Int.  Congress  on  Hygiene  and  Demography,  Washington, 
1913,  2,  p.  438. 


BASAL   KATABOLISM. 


95 


TABLE  12. — Minimum  heat-production  of  new-born  infants. 


Heat  produced  (computed) 

Average 

per  24  hours. 

Body- 

rectal  tem- 

Per square  meter 

Sub- 
ject 

XT 

Sex. 

weight 
with- 
out 

Length. 

Age. 

perature. 

Pulse- 
rate. 

Per 

(Lissauer, 
10.3  X/W2). 

No. 

cloth- 

Total. 

kilo- 

Per 

ing. 

gram. 

°Cent. 

°Fahr. 

Total. 

•centi- 

meter of 

i 

length.1 

kg. 

cm. 

cal. 

cal. 

cal. 

cal. 

2 

F. 

3.80 

53 

6|  days 

36.8 

98.2 

99 

152 

40 

606 

11.4 

3 

M. 

3.63 

52 

2£  days 

37.0 

98.6 

97 

166 

46 

685 

13.2 

4 

F. 

3.28 

46.5 

2  days 

37.2 

99.0 

105 

139 

43 

612 

13.2 

5 

M. 

3.82 

52.5 

7  hrs. 

36.9 

98.4 

112 

137 

36 

544 

6 

M. 

4.32 

52 

3£  days 

37.0 

98.6 

116 

191 

44 

697 

13A 

8 

M. 

3.48 

51 

2  days 

36.8 

98.3 

117 

160 

45 

673 

13.2 

9 

F. 

4.04 

51 

2  days 

37.3 

99.2 

109 

178 

44 

677 

13.3 

10 

M. 

3.45 

52 

2  days 

36.8 

98.2 

116 

162 

48 

694 

13.3 

12 

F. 

4.17 

52.5 

5  days 

37.0 

98.6 

112 

171 

41 

639 

12.2 

13 

F. 

3.25 

50 

2  days 

37.1 

98.7 

113 

138 

43 

612 

12.2 

15 

M. 

3.64 

50 

4  days 

37.0 

98.6 

122 

162 

44 

665 

13.3 

16 

F. 

4.03 

53 

2|  days 

37.1 

98.8 

113 

175 

44 

670 

12.6 

17 

F. 

3.66 

52.5 

15  hrs. 

36.8 

98.3 

118 

174 

48 

713 

18 

M. 

2.84 

50.5 

7  days 

36.6 

97.9 

105 

108 

38 

519 

10.3 

19 

M. 

3.50 

53 

1^  days 

36.9 

98.5 

114 

155 

44 

653 

12.3 

20 

F. 

3.54 

52 

3|  days 

36.8 

98.3 

110 

153 

43 

638 

12.3 

21 

F. 

2.92 

50 

2  days 

36.9 

98.4 

121 

136 

47 

645 

12.9 

22 

F. 

2.72 

49 

1\  days 

36.8 

98.2 

114 

128 

47 

635 

13.0 

25 

M. 

3.32 

51.5 

4  days 

36.9 

98.5 

123 

158 

47 

686 

13.3 

26 

F. 

3.46 

50 

5  days 

37.2 

98.9 

113 

151 

44 

645 

12.9 

27 

M. 

3.58 

52 

4  days 

37.1 

98.8 

111 

169 

48 

703 

13.5 

29 

F. 

3.37 

50 

2^  days 

37.4 

99.3 

112 

150 

45 

652 

13.0 

30 

M. 

3.33 

51 

2  days 

37.1 

98.7 

114 

144 

43 

623 

12.2 

31 

M. 

3.56 

53.5 

4  days 

37.1 

98.7 

117 

158 

45 

662 

12.4 

32 

M. 

3.42 

47.5 

2|  days 

36.9 

98.5 

116 

140 

41 

604 

12.7 

33 

M. 

3.73 

52 

5  days 

37.1 

98.7 

129 

153 

41 

617 

11.9 

34 

F. 

2.90 

50.5 

2  days 

37.2 

98.9 

115 

134 

47 

638 

12.6 

35 

F. 

4.33 

54 

4  days 

37.2 

98.9 

109 

175 

41 

640 

11.9 

36 

M. 

3.33 

53 

21  hrs. 

37.6 

99.6 

129 

154 

46 

670 

37 

F. 

2.49 

46.5 

13  hrs. 

36.8 

98.3 

119 

99 

40 

522 

38 

F. 

3.90 

51.5 

\\  days 

37.4 

99.3 

127 

156 

40 

610 

ii.8 

39 

F. 

2.95 

50 

9  hrs. 

36.5 

97.7 

105 

113 

38 

533 

40 

F. 

2.78 

49.5 

4|  days 

37.4 

99.4 

111 

134 

48 

655 

i3i2 

42 

F. 

3.95 

54 

3  days 

37.2 

98.9 

113 

176 

45 

684 

12.7 

43 

F. 

3.62 

50 

2  days 

37.6 

99.6 

119 

165 

46 

682 

13.6 

44 

F. 

3.57 

51 

2  hrs. 

36.9 

98.4 

103 

136 

38 

567 

45 

F. 

2.56 

46.5 

1  day 

36.6 

97.9 

110 

107 

43 

558 

46 

M. 

3.83 

51.5 

5  hrs. 

37.2 

99.0 

126 

152 

40 

603 

47 

M. 

3.51 

52 

5  hrs. 

37.5 

99.5 

107 

143 

41 

601 

48 

F. 

4.52 

54.5 

6  days 

36.9 

98.4 

132 

188 

42 

667 

12.2 

49 

F. 

2.75 

47.5 

4  days 

36.9 

98.5 

114 

130 

47 

638 

13.4 

50 

F. 

2.75 

48.5 

1  day 

36.4 

97.6 

89? 

142 

52 

700 

51 

M. 

3.73 

52.5 

2  days 

36.9 

98.5 

96 

154 

42 

623 

11.9 

52 

F. 

3.54 

50 

2?  days 

37.2 

99.0 

114 

138 

39 

579 

11.6 

53 

M. 

2.87 

47.5 

2  days 

37.7 

99.9 

126 

143 

50 

684 

14.4 

54 

M. 

3.31 

50 

\\  days 

37.1 

98.7 

106 

129 

39 

563 

11.3 

55 

M. 

3.45 

50 

16  hrs. 

36.9 

98.4 

124 

151 

44 

641 

56 

M. 

3.19 

51.5 

4  days 

36.9 

98.4 

121 

150 

47 

669 

13.0 

57 

M. 

3.75 

54 

22  hrs. 

36.9 

98.5 

105 

153 

40 

611 

Computed  only  for  infants  of  ages  between  1|  and  6  days  inclusive.     See  fig.  10,  p.  107. 


96 


PHYSIOLOGY    OF   THE    NEW-BORN    INFANT. 


TABLE  12. — Minimum  heat-production  of  new-born  infants — Continued. 


Age. 

Heat  produced  (computed) 

Average 

per  24  hours. 

Sub- 
ject 

"NTn 

Sex. 

Body- 
weight 
with- 
out 

Length. 

rectal  tem- 
perature. 

Pulse- 
rate. 

Per 

Per  square  meter 
(Lissauer 
10.3  v'w*). 

l^i  O. 

cloth- 

Total. 

kilo- 

Per 

ing. 

gram. 

°Cent. 

°Fahr. 

Total. 

centi- 

meter of 

length.1 

kg. 

cm. 

cal. 

cal. 

cal. 

cal. 

58 

F. 

3.01 

49 

1 

day 

37.2 

98.9 

Ill 

139 

46 

647 

59 

F. 

3.60 

52 

IT 

days 

37.1 

98.8 

112 

150 

42 

621 

11.3 

60 

M. 

3.60 

52 

4 

days 

37.0 

98.6 

117 

149 

42 

617 

11.9 

61 

M. 

3.26 

49.5 

21 

^hrs. 

36.6 

97.8 

121 

123 

38 

542 

62 

M. 

3.30 

49.5 

3 

days 

36.8 

98.3 

116 

134 

41 

588 

11.9 

63 

F. 

2.37 

47.5 

3 

days 

37.2 

98.9 

125 

109 

46 

596 

12.5 

64 

F. 

3.37 

48 

7 

hrs. 

36.7 

98.1 

98 

128 

38 

552 

65 

F. 

2.63 

49 

2 

days 

36.8 

98.2 

116 

127  ;  48 

644 

13.1 

66 

M. 

3.19 

51 

14 

hrs. 

36.3 

97.4 

103 

122  1  38 

543 

67 

M. 

4.74 

54 

3 

days 

37.1 

98.7 

122    193  .  41 

669 

12^4 

68 

M. 

2.12 

46 

4 

days 

36.8 

98.3 

113 

103    48 

604 

13.1 

69 

M. 

3.44 

50 

19 

hrs. 

36.9 

98.5 

110 

142  !  42 

609 

70 

M. 

3.56 

51 

2 

days 

36.9 

98.5 

109 

153 

43 

640 

12.5 

71 

M. 

3.96 

53.5 

3 

days 

36.8 

98.2 

106 

172 

44 

667 

12.5 

72 

M. 

3.29 

50.5 

2\ 

days 

36.7 

98.0 

110 

157 

48 

687 

13.6 

73 

M. 

3.63 

50 

7 

hrs. 

36.8 

98.2 

106 

164 

45 

673 

74 

M. 

3.63 

52 

2 

days 

36.8 

98.3 

94 

156 

43 

640 

12^3 

75 

M. 

2.65 

47.5 

U 

days 

36.6 

97.9 

100 

132 

50 

664 

14.0 

76 

M. 

3.16 

50 

13 

hrs. 

36.7 

98.0 

101 

137 

44 

618 

78 

M. 

2.48 

47 

12 

hrs. 

36.4 

97.6 

101 

109 

44 

577 

79 

F. 

4.14 

52.5 

4 

hrs. 

36.9 

98.4 

116 

153 

37 

575 

80 

M. 

3.47 

51.5 

3 

hrs. 

36.4 

97.6 

109 

128 

37 

542 

81 

F. 

3.29 

50 

4 

hrs. 

36.9 

98.4 

114 

167 

51 

732 

82 

M. 

2.74 

49 

3 

hrs. 

36.4 

97.6 

101 

95 

35 

470 

83 

M. 

3.73 

52 

3 

hrs. 

37.2 

99.0 

131 

148 

40 

597 

84 

F. 

4.11 

54 

21 

hrs. 

36.5 

97.7 

109 

133 

32 

504 

85 

M. 

3.52 

52 

9 

hrs. 

36.8 

98.2 

109  i  144    41 

605 

86 

F. 

3.32 

51 

6 

hrs. 

36.6 

97.8 

103    120    36 

524 

87 

M. 

3.94 

51 

3^ 

hrs. 

37.3 

99.2 

118    146 

37 

567 

88 

F. 

2.62 

47.5 

9 

hrs. 

36.8 

98.3 

96    122    47 

623 

89 

M. 

3.24 

49.5 

8 

hrs. 

36.7 

98.0 

107    124    38 

549 

90 

M. 

3.00 

50 

21 

days 

36.8 

98.2 

86 

138    46 

641 

12.S 

91 

F. 

3.33 

49.5 

13 

hrs. 

37.4 

99.4 

113 

140 

42 

609 

92 

F. 

3.78 

51 

4 

hrs. 

36.6 

97.8 

112 

157 

42 

628 

93 

M. 

3.53 

50.5 

4 

hrs. 

36.8 

98.2 

127 

136 

39 

573 

94 

M. 

3.20 

50 

3i 

hrs. 

36.8 

98.2 

117 

136 

43 

607 

95 

F. 

2.84 

46.5 

5^ 

hrs. 

36.2 

97.1 

123 

100 

35 

483 

96 

F. 

3.23 

51.5 

3i 

hrs. 

36.6 

97.8 

99 

113 

35 

502 

97 

F. 

2.82 

48 

4i 

hrs. 

36.1 

96.9 

113 

112 

40 

542 

98 

F. 

2.86 

47.5 

5 

hrs. 

36.2 

97.1 

102 

98 

35 

471 

99 

M. 

3.58 

51.5 

2\ 

hrs. 

36.9 

98.4 

103 

122 

34 

508 

100 

M. 

4.65 

54 

hrs. 

37.1 

98.8 

130 

186 

40 

648 

101 

M. 

3.88 

51.5 

5J 

hrs. 

36.7 

98.0 

109 

126 

32 

496 

103 

F. 

3.29 

49 

2\  hrs. 

37.5 

99.5 

125 

130 

40 

570 

104 

M. 

3.32 

51 

3 

hrs. 

36.4 

97.6 

107 

105 

32 

459 

Average  of 

94  sub- 

jects. .  . 

3.40 

50.5 

2 

days 

36.9 

98.4 

112 

143 

42 

612 

Computed  only  for  infants  of  ages  between  \\  and  6  days  inclusive.     See  fig.  10,  p.  107. 


BASAL    KATABOLISM. 


97 


In  table  12  the  minimum  metabolism  is  expressed  first  as  the  total 
heat-production  in  24  hours;  second,  as  the  heat-output  per  kilogram 
of  body-weight  per  24  hours ;  and  third,  as  the  heat-output  per  square 
meter  of  body-surface  per  24  hours.  To  explain  these  values  further 
we  have  added  the  records  for  the  body-weight  without  clothing,  the 
length,  the  age,  the  average  rectal  temperature,  and  the  pulse-rate  for 
the  periods  of  observation  included  in  this  table. 

TOTAL  MINIMUM  HEAT-PRODUCTION  PER  24  HOURS. 

It  will  be  seen  that  on  the  basis  of  the  total  minimum  heat-production 
per  24  hours  new-born  infants  may  range  from  193  calories  found  with 
subject  67  to  a  minimum  of  95  calories  found  with  subject  82.  With 
so  large  a  number  of  values  as  are  given  in  table  12  it  is  difficult  to 
discover  any  direct  relationship  between  the  body-weight  and  the  total 
heat-output.  The  results  have  therefore  been  represented  graphically 
in  figure  4,  in  which  the  total  heat-output  per  24  hours  has  been 


4.7 


4.4 


4.1 


I  3.8 


3,5 


3.2 
2.9 
2.6 
2.3 
2.0 


^ 


90    100    110    120    130    140    150    160    170    180    190   200 

Calories  per  24  Hours 

FIG.  4. — Minimum  heat-production  of  new-born  infants  per  24  hours  referred  to 

the  body-weight. 

plotted  against  the  actual  body-weight  of  the  individual  infants  at  the 
time  the  metabolism  was  measured.  The  approximate  average  value 
is  indicated  in  the  chart  by  a  heavy  black  line.  As  a  matter  of  fact, 
this  line  represents  a  value  of  42  calories  per  kilogram  of  body-weight 
per  24  hours. 


98  PHYSIOLOGY   OF   THE   NEW-BORN   INFANT. 

Although  one  would  expect  with  a  large  number  of  normal  new-born 
infants  to  find  a  tendency  towards  constancy  in  the  minimum  metabo- 
lism, this  chart  shows  clearly  that  there  is  no  such  constancy,  for  while 
in  general  there  is  a  rough  relationship  between  the  total  body-weight 
and  the  total  minimum  metabolism,  in  that  for  the  most  part  the 
infants  with  the  larger  body-weight  have  the  larger  metabolism,  yet 
wide  deviations  from  the  average  value  are  found. 

Recently  it  has  been  the  custom  among  some  writers  on  metabolism 
to  consider  a  plus  or  minus  metabolism  of  10  per  cent  as  a  possible  nor- 
mal fluctuation.  Although  the  arbitrary  selection  of  this  range  seems 
questionable  and  we  are  unable  to  see  what  particular  value  the  indi- 
vidual normal  figures  may  have  when  the  variation  may  admittedly 
be  =*=  10  per  cent,  we  have  indicated  these  limits  on  the  chart  by  light 
lines  above  and  below  the  heavier  line  showing  the  average  value. 
Even  under  these  circumstances  we  find  that  a  large  number  of  the 
plotted  figures  lie  outside  of  the  supposedly  acceptable  limits  of  varia- 
tion, for  13  points  are  above  the  upper  light  line  and  at  least  17 
points  below  the  lower  light  line;  in  other  words,  some  30  values  lie 
outside  of  the  ±10  per  cent  limits  of  variation.  Perhaps  the  most 
striking  illustration  of  this  fact  is  that  of  an  infant  weighing  4.1  kilo- 
grams and  having  a  total  heat-output  per  24  hours  of  133  calories. 
While  the  majority  of  the  results  obtained  were  well  within  the  ±10 
per  cent  limits,  yet,  as  our  observations  were  made  with  new-born 
infants,  presumably  healthy  organisms,  which  should  be  perfectly  com- 
parable, it  is  somewhat  surprising  that  variations  are  found  as  large  as 
and,  indeed,  much  larger  than  =*=  10  per  cent. 

MINIMUM    HEAT-OUTPUT  PER  KILOGRAM  OF  BODY-WEIGHT 
PER  24  HOURS. 

The  highest  value  for  the  minimum  heat-production  in  this  series 
of  observations  was  secured  with  infant  No.  67,  who  had  a  body- weight 
of  4.74  kg.,  this  being  the  largest  body- weight  of  any  of  the  infants; 
the  lowest  minimum  heat-production  was  found  with  infant  No.  82, 
whose  body-weight  was  only  2.74  kg.,  although  some  of  the  infants 
had  an  even  smaller  body-weight  than  this.  It  is  obvious,  therefore, 
that  body-weight  plays  an  important  r61e  in  the  amount  of  the  katabo- 
lism  and  the  heat-production  per  unit  of  weight  must  be  considered. 
The  values  for  the  heat-production  per  kilogram  of  body-weight  given 
in  table  12  vary  from  52  calories  per  kilogram  with  infant  No.  50  to  32 
calories  per  kilogram  with  infants  Nos.  84,  101,  and  104.  It  is  thus 
clear  that,  even  per  kilogram  of  body-weight,  healthy  new-born  infants 
may  vary  widely  in  their  energy  output. 

Here  again  the  general  trend  may  be  more  easily  seen  in  the  form  of 
a  chart,  and  the  values  are  therefore  given  on  this  basis  in  figure  5, 
which  shows  very  clearly  the  wide  variations  in  the  values.  Prac- 
tically no  approximation  to  regularity  is  apparent,  although  a  con- 


BASAL    KATABOLISM. 


siderable  number  of  the  points  lie  within  ±10  per  cent  of  the  average 
value  of  42  calories.  If  we  draw  lines  at  38  and  46  to  represent  these 
limits  of  variation,  we  find  that  13  values  lie  outside  of  the  limits  on  the 
one  side  and  18  values  on  the  other,  there  being  in  all  some  33  per  cent 
of  the  total  number  outside  of  the  limits  of  variation.  To  indicate  a 
true  average  value  for  a  living  organism  on  the  basis  of  weight  alone 
appears,  therefore,  to  be  extremely  difficult,  for  even  with  these  normal 
new-born  infants,  which  are  presumably  more  directly  comparable 
than  any  other  class  of  human  beings,  we  still  find  wide  variations. 


4.7 

4.4 
4.1 

1  3.8 
k 

•fa-5 
lu 

2.9 
2.6 
2.3 

2'°3 

• 

• 

• 

• 

• 

f 

• 

. 

. 

• 

• 

• 

. 

1 

s 

: 

2         34         36         38         40         42         44         45         48         50         5, 

Calories  per  Kilo,  per  24  Hours 

FIG.  5. — Minimum  heat-production  of  new-born  infants  per  kilogram  per  24 
hours  referred  to  the  body-weight. 

MINIMUM  HEAT-OUTPUT  PER  SQUARE  METER  PER  24  HOURS. 

Since  the  cube  root  of  the  square  of  the  body-weight  represents  the 
general  law  of  growth,  and  since  physiologists,  basing  their  belief  upon 
the  observations  of  Bergmann,1  Rubner,2  and  Richet,3  have  been 
inclined  to  ascribe  a  particular  significance  to  the  relationship  between 
the  body-surface  and  the  metabolism,  the  results  computed  on  the 
basis  of  the  heat-output  per  square  meter  of  body-surface  per  24  hours 
have  been  included  in  table  12.  In  our  earlier  publication4  it  was 

Bergmann  and  Leuckart,  Anatomisch-physiol.  Uebersicht  des  Thierreichs,  Stuttgart,  1852, 
p.  272.  See  also,  Bergmann,  Ueber  die  Verhaltnisse  der  Warmeokonomie  der  Thiere  zu  ihrer 
Grosse,  Gottingen,  1848,  p.  9. 

2Rubner,  Zeitschr.  f.  Biol.,  1883,  19,  p.  545. 

3Richet,  Archives  de  Physiol.  norm,  et  path.,  1885,  15,  3d  ser.,  p.  237. 

'Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1914,  p.  166;  Benedict  and  Talbot, 
Am.  Journ.  Diseases  of  Children,  1914,  8,  p.  48. 


100  PHYSIOLOGY   OF   THE   NEW-BORN   INFANT. 

shown  that  one  of  the  greatest  factors  influencing  thermogenesis,  i.  e., 
the  active  mass  of  protoplasmic  tissue,  probably  develops  according 
to  the  general  fundamental  law  of  growth  as  expressed  by  the  cube 
root  of  the  square  of  the  body- weight.  We  feel  wholly  justified,  there- 
fore, in  attempting  to  study  the  heat-production  of  these  infants  on 
the  empirical  basis  of  the  heat-output  per  square  meter  of  body-surface 
per  24  hours. 

The  actual  measurement  of  the  body-surface  of  these  infants  was 
impossible,  as  the  methods  used  by  Meeh  and  Lissauer  were  precluded 
and  no  other  method  giving  accurate  results  was  available.  At  the 
moment  of  writing  a  method  which  promises  well,  namely,  the  Du 
Bois  formula,  makes  it  not  at  all  impossible  that  body-measurements 
may  be  practicable  in  future  investigation  of  this  type.  As  the  data 
regarding  the  body-surface  of  these  infants  could  not  be  obtained  by 
means  of  actual  measurement,  we  employed  in  our  calculations  the  for- 
mula of  Lissauer,  in  which  the  constant  10.3  is  multiplied  by  the  cube 
root  of  the  square  of  the  body-weight. 

The  results  thus  obtained  show  that  the  average  minimum  heat- 
production  per  square  meter  of  body-surface  for  the  94  infants  was  612 
calories  per  square  meter  per  24  hours.  The  largest  minimum  value 
was  732  calories  with  infant  No.  81  and  the  smallest  459  calories  with 
infant  No.  104.  Even  on  this  basis,  which  is  supposed  to  equalize  not 
only  all  animals  of  similar  species  but  also  animals  of  different  species, 
we  do  not  find  comparable  values  for  these  infants  throughout  the 
whole  series. 

For  a  better  visualization  of  the  values  for  the  heat-output  com- 
puted on  this  basis  and  given  in  table  12,  the  minimum  heat-production 
per  square  meter  of  body-surface  per  24  hours  has  been  plotted  against 
the  body-weight.  (See  fig.  6.)  Here  also  we  find  very  wide  deviations 
from  the  average  value  of  612  calories.  Using  again,  for  the  purpose  of 
discussion,  the  hypothetical  limits  of  =*=  10  per  cent,  i.  e.,  675  calories  and 
550  calories,  respectively,  we  find  that  there  are  18  values  which  are 
more  than  10  per  cent  below  the  average  value  and  13  over  10  per 
cent  above  the  average  value.  Thus  in  practically  one-third  of  our 
observations  the  results  obtained  vary  more  than  =*=  10  per  cent  from 
the  average  value. 

In  considering  the  results  obtained  with  our  infants  and  graphically 
shown  in  figure  6,  it  is  of  particular  interest  to  refer  to  the  previous 
conception  regarding  the  heat-production  per  square  meter  of  body- 
surface  of  infants.  Although  infants  have  rarely  been  studied  in  the 
first  week  of  post-natal  life,  the  prevailing  opinion  of  physiologists  has 
been  that  very  small  and  very  young  animals  have  proportionally  a 
much  larger  heat-production  than  has  the  adult  organism.  From  the 
review  of  the  earlier  literature  given  in  our  first  report1  it  will  be  seen 

Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1914,  p.   11;    also,  Am.  Journ. 
Diseases  of  Children,  1914,  8,  p.  3  and  43. 


BASAL   K  AT  ABOLISH. 


101 


that  the  general  belief  was  that  infants  produced  not  far  from  1,000 
calories  per  square  meter  of  body-surface  in  common  with  that  sup- 
posedly produced  by  other  living  organisms.  The  first  considerable 
reduction  in  this  figure  is  noted  in  the  writings  of  Schlossmann  and 
Murschhauser,1  in  which  they  point  out  that  the  basal  value  is  866 
calories  per  square  meter.  That  this  compares  favorably  with  values 
obtained  upon  man  is  shown  by  Schlossmann  and  Murschhauser  in  an 
interesting  way  from  the  results  of  a  single  period  selected  from  one  of 
the  earlier  experiments  of  Atwater  and  his  associates,  in  which  a  heat- 
production  of  828  calories  per  square  meter  was  observed. 


4.7 
4.4 
4.1 
3.8 
3.5 
3.2 
2.9 
2.6 
2.3 

2-2 

• 

• 

• 

. 

• 

• 

. 

*    * 

• 

'    . 

, 

* 

-  • 

- 

. 

• 

• 

•    . 

. 

• 

• 

• 

. 

• 

• 

' 

• 

• 

• 

• 

. 

• 

50       480        500        520        540        560        580        600       620        640       660       680        700        720       74 
Calories  per  Sq.  Meter  per  24  Hours 

FIG.  6. — Minimum  heat-production  of  new-born  infants  per  square  meter  of  body-surface 
per  24  hours  referred  to  the  body-weight. 

We  may  then  say  that  up  to  the  present  time  the  general  opinion 
has  been  that  young  infants  had  a  larger  metabolism  than  adults,  that 
such  measurements  as  were  made  previous  to  the  observations  of  Schloss- 
mann and  Murschhauser  ascribe  to  the  infant  a  heat-production  of 
1,000  calories  per  square  meter  of  body-surface,  and  that  the  figure  of 
Schlossmann  and  Murschhauser  reduces  this  value  to  866  calories  per 
square  meter  of  body-surface.  It  is  of  further  interest  that  this  value 
of  866  calories  per  square  meter  was  obtained  and  reported  by  Schloss- 
mann and  Murschhauser  in  full  recognition  of  the  significance  of  com- 
plete muscular  repose  during  the  observations,  as  is  evidenced  by  their 
painstaking  ocular  notations  of  the  degree  of  muscular  repose  which 
were  made  by^a  specially  trained  assistant. 


Schlossmann  and  Murschhauser,  Biochem.  Zeitschr.,  1910,  26,  p.  32. 


102  PHYSIOLOGY  OF  THE  NEW-BORN   INFANT. 

By  reference  to  table  12,  it  will  be  seen  that  the  vahie  of  866  calories 
is  over  100  calories  higher  than  the  higVM  value  there  recorded,  for 
only  3  observations  are  above  700  calories  per  square  meter  of  body- 
surface,  these  being  obtained  with  infants  17,  27,  and  81,  who  had  a 
heat-production  per  square  meter  of  713,  703,  and  732  calories,  respec- 
tively. The  average  minimum  heat-production  of  612  calories  per 
square  meter  is  254  calories  less  than  the  minimum  figure  of  Schloss- 
rnann  and  Murschhauser. 

Perhaps  no  better  illustration  than  this  can  be  found  of  the  difficul- 
ties of  securing  accurate  information  regarding  the  probable  trend 
of  the  metabolism  of  any  group  of  individuals,  in  which  one  case 
that  was  carefully  and  continuously  studied  gave  a  value  of  866  calories 
per  square  nieter  of  body-surface,  and  a  later  research,  in  which  100 
or  more  cases  were  studied,  gave  results  very  much  lower,  no  value 
being  secured  within  essentially  130  calories  of  the  minimum  obtained 
by  the  previous  investigators.  The  cause  for  this  discrepancy  may 
readily  be  found,  we  believe,  in  the  inherent  difficulties  in  obtaining 
metabolism  measurements  when  the  experimental  periods 


must  of  necessity  be  of  several  hours  duration,  as  was  the  cam  with 
Schlossmann  and  Murschhauser.  Had  these  observers  been  able  to 
measure  the  metabolism  of  their  infant  in  selected  half-hour  periods, 
we  have  no  doubt  that  their  value  of  866  calories  would  have  been 
materially  reduced. 

The  value  of  866  calories  reported  by  Schlossmann  and  Murschhauser 
was  not  obtained  with  a  new-born  infant,  but  at  the  time  their  observa- 
tions were  published  it  was  the  general  impression  among  pediatricians 
that  the  metabolism  of  the  new-born  infant  would  be  even  higher  per 
unit  of  surface  than  that  of  an  infant  several  months  old.  Accordingly, 
the  difference  between  our  average  minimum  value  of  612  calories  and 
the  minimum  value  of  Schlossmann  and  Murschhauser  of  866  calories 
per  square  meter  of  body-surface  is,  to  say  the  least,  most  striking. 

It  should  likewise  be  borne  in  mind  that  it  is  unpractical  to  use  here  for 
comparison  the  heat-production  per  square  meter  per  24  hours  recorded 
for  the  infants  studied  in  our  previous  research,1  for  these  latter  include 
a  large  number  of  atrophic  infants  whose  metabolism  is  admittedly 
above  normal.  Although  our  material  is  slowly  accumulating  for  an 
estimation  of  the  metabolism  of  perfectly  normal  infants  from  the  time 
of  birth  to  the  age  of  2  years,  we  are  not  yet  in  a  position  to  draw  con- 
clusions that  will  necessarily  withstand  subsequent  addition  of  data:  we 
prefer,  therefore,  to  defer  the  making  of  general  deductions  until  later. 

INFLUENCE  OF  AGE  UPON  THE  KATABOUSM. 

A  general  inspection  of  the  values  given  in  table  12  indicates  that  in 
the  first  week  of  life  there  is  some  connection  between  the  age  and  the 

^Benedict  and  Talbot.  Carnegie  lust.  Wash.  Pub.  N<x  301.  1914:  aba.  Am.  Jouru.. 
of  Children.  1914.  &  p-  1. 


BASAL   KATABOLISM. 


103 


total  katabolism.  Although  little  in  the  nature  of  such  a  relationship 
may  be  expected  in  the  first  hours  after  birth,  for  during  the  first  24 
hours  of  life  there  must  certainly  be  a  profound  readjustment  of  the 
organism  as  a  result  of  the  radical  change  hi  environment,  yet  in  order 
that  a  study  may  be  made  of  this  possible  relationship,  three  charts 
have  been  plotted  in  which  the  total  heat-production  per  24  hours,  the 
heat-production  per  kilogram  of  body-weight,  and  the  heat-production 
per  square  meter  of  body-surface  have  been  plotted  against  the  age, 
the  minimum  figures  given  in  table  12  being  used  hi  all  cases.  (See 
figures  7,  8,  and  9.) 

IXTLtnCMCE  OF  AOB    CPOM  TUB   HEAT-PR00UCT10W  IV  THE    FlB0T  DAT. 

The  total  heat-production  and  the  age  hi  days  at  the  time  of  measure- 
ment are  compared  hi  figure  7,  from  which  it  will  be  seen  that  there  is  a 
general  tendency  for  the  low  values  for  the  heat-production  to  occur 


I 


90         100        HO        120        130        140       ISO        160        170        180        190       200 
Cabrfet  ftr  24  HIM* 

Fn«.  7. — Minimum  beat-producikm  of  new-born  infanta  per  24  bourn  referred  to  af*, 

on  the  first  day  of  life.  The  chart  does  not  take  into  consideration  the 
differences  hi  body-weight,  but  this  is  done  hi  figure  8,  hi  which  the 
heat-production  per  kilogram  of  body-weight  per  24  hours  is  plotted 
against  the  age.  In  figure  8,  also,  we  find  that  nearly  all  of  the  low 
values,  such  as  those  under  40  calories  per  kilogram  per  24  hours, 
appear  on  the  first  day,  even  when  the  weight  of  the  infant  is  taken 
into  account. 

This  tendency  is  shown  even  more  strikingly  in  figure  9,  in  which 
the  heat-production  per  square  meter  of  body-surface  per  24  hours  is 
plotted  against  the  age,  for  all  but  4  of  the  values  below  600  calories 
are  found  on  the  first  day.  It  is  likewise  of  interest  to  note  that  the 
two  highest  values  obtained  with  our  infants  for  the  heat-production 
per  square  meter  of  body-surface  per  24  hours  were  also  found  on  this 


104 


PHYSIOLOGY   OF   THE   NEW-BORN   INFANT. 


day.  In  an  attempt  to  study  the  heat-production  more  closely,  the 
chart  has  been  so  plotted  as  to  show  the  values  obtained  on  each  half 
day.  We  find  but  little  difference  between  the  first  and  last  halves  of 
the  first  day,  however,  as  the  number  of  observations  in  the  second  12 
hours  of  life  were  relatively  few.  As  a  matter  of  fact,  all  values  below 
520  calories  per  square  meter  of  body-surface  were  obtained  inside  of 
the  first  12  hours  of  life. 

From  figures  7,  8,  and  9,  therefore,  it  is  evident  that  in  our  problem 
of  studying  the  metabolism  of  infants  during  the  first  week  of  post- 
natal life  we  have  two  distinct  phases  to  consider:  (1)  the  metabolism 
on  the  first  day  of  birth,  and  (2)  the  metabolism  on  the  remaining  5  or 
6  days  of  the  first  week.  While  all  of  the  charts  thus  far  studied 


1-3 

2 
1 


32         34 


36 


38          40          42         44          46 
Calories  per  Kilo,  per  24  Hours 


48 


50         52 


Fio.  8. — Minimum  heat-production  of  new-born  infants  per  kilogram  of 
body-weight  per  24  hours  referred  to  age. 

indicate  clearly  that  there  is  no  approximation  to  uniformity  shown 
in  the  metabolism  of  new-born  infants  during  the  first  week  of  life,  the 
analysis  just  made  shows  that  a  large  part,  if  not  indeed  the  greater 
part,  of  the  extreme  values  found  in  our  observations  may  be  attributed 
to  the  measurements  obtained  during  the  first  24  hours  of  life.  Hence 
our  general  conclusion  with  regard  to  the  metabolism  of  new-born 
infants  holds  true,  particularly  for  the  first  day  of  life,  namely,  that 
there  is  no  relationship  between  the  total  metabolism  and  either  the 
body-weight  or  the  body-surface.  We  have  to  consider,  therefore,  if, 
after  eliminating  the  first  day  of  post-natal  life,  in  which  there  is 
admittedly  a  profound  physiological  readjustment  inside  the  organism, 
any  tendency  towards  uniformity  may  be  noted  in  the  remaining  days 
of  the  week. 


BASAL  KATABOLISM. 


105 


INFLUENCE  OF  AGE  ON  THE  HEAT-PRODUCTION  FROM  THE  SECOND  TO  THE  SEVENTH  DAY. 

With  a  number  of  infants  experiments  were  made  practically  every 
day  during  the  first  week  of  life.  While  it  was  not  possible  to  obtain 
values  showing  the  minimum  metabolism  for  all  of  these  infants  on 
the  succeeding  days  of  the  week,  we  have  been  able  to  collect  data  for 
a  considerable  number  of  the  infants  for  the  first  8  days  of  life  which 
show  an  approximately  minimum  metabolism.  As  for  the  first  5  days 
of  the  week  the  data  were  obtained  from  35  to  56  subjects,  and  even  on 


64 

°z 

6 

1 

5 

«! 

4 

| 

°*i 

t 

3 

22 

z 

«i 
1 
A 

°4 

• 

• 

»•,. 

• 

• 

• 

•      • 

... 

• 

*  *  • 

: 

:•" 

. 

• 

• 

• 

• 

• 

60   480   500   520   540   560   580   600   620   640   660   680   700   720   74 

Calories  per  Sq.  Meter  per  24  Hours 

FIG.  9. — Minimum  heat-production  of  new-born  infants  per  square  meter  of  body-surface 
per  24  hours  referred  to  age. 

the  last  3  days  from  6  to  16  subjects,  we  may  fairly  say  that  they  are 
distinctly  comparable.  While  these  values  do  not  represent  the  actual 
minimum  metabolism,  they  probably  do  show,  in  general,  the  basal 
metabolism;  they  are  therefore  compared  in  table  13,  in  which  are 
given:  first,  the  number  of  subjects  averaged  for  each  day,  and  second, 
the  average  heat-production  per  square  meter  of  body-surface  per  24 
hours  for  the  successive  days. 


106 


PHYSIOLOGY    OF   THE    NEW-BORN    INFANT. 


Even  these  approximately  minimum  metabolism  values  show  a  heat- 
production  per  square  meter  of  body-surface  which  is  considerably 
lower  on  the  first  day  than  on  the  other  days  of  the  week.  After  the 
first  day  the  values  remain  essentially  constant  at  660  or  670  calories 
until  the  eighth  day,  the  values  for  6  subjects  on  this  last  day  averaging 
702  calories. 

TABLE  13. — Approximate  basal  metabolism  of 
infants  during  first  8  days  after  birth. 


Average  heat- 

Age. 

No.  of 
subjects. 

production  (com- 
puted) per  square 

meter  per  24  hours. 

days. 

cat. 

1 

56 

592 

2 

47 

661 

3 

49 

676 

4 

46 

677 

5 

35 

659 

6 

16 

689 

7 

8 

652 

8 

6 

702 

If  we  turn  again  to  figure  9,  in  which  the  absolutely  minimum  values 
are  shown,  we  find  that  there  is  a  distinct  tendency  for  the  minimum 
values  for  the  days  subsequent  to  the  first  day  of  life  to  group  about  a 
vertical  line  corresponding  to  an  average  of  approximately  640  calories 
per  square  meter.  If  the  limits  of  variation  used  with  the  other  charts 
are  applied,  it  will  be  seen  that  practically  all  of  the  data  for  the  last  6 
days  lie  between  580  and  700  calories  per  square  meter  of  body-surface, 
the  single  exception  being  that  of  the  7-day-old  infant  No.  18,  with  the 
extraordinarily  low  heat-production  per  square  meter  of  519  calories. 
Aside  from  this  particular  case,  therefore,  all  of  the  plotted  values  sub- 
sequent to  the  first  day  of  life  lie  inside  of  the  =*=  10  per  cent  variation 
from  the  average  value  of  approximately  640  calories.  If  the  plus  or 
minus  variation  of  10  per  cent  is  accepted  as  approximating  a  physio- 
logical law,  we  may  consider  this  a  verification  of  the  fact  that  after  the 
first  24  hours  the  heat-production  of  new-born  infants  during  the  first 
week  of  lif  e  is  approximately  640  calories  per  square  meter  of  body-sur- 
face, all  values  lying  inside  the  limits  of  ±10  per  cent  of  this  average. 

INFLUENCE  OF  LENGTH  UPON  THE  BASAL  KATABOLISM. 

In  our  study  a  large  number  of  plots  were  made  in  an  attempt  to 
establish  some  relationship  between  the  metabolism,  the  body-surface, 
length,  weight,  age,  and  even  pulse-rate  and  body-temperature,  as  it 
was  believed  that  the  data  obtained  in  the  research  were  sufficiently 
extensive  to  justify  a  thorough  search  for  a  mathematical  relationship 
between  the  measured  factors.  In  a  close  examination  of  the  original 
draft  of  figure  9,  on  which  were  noted  the  lengths  of  the  infants  repre- 


BASAL    KATABOLISM. 


107 


sented  by  each  point,  it  was  observed  that  there  was  a  distinct  tendency 
for  the  shorter  infants  to  have  a  lower  heat-production  per  square  meter 
of  body-surface  than  the  heat-production  of  the  longer  infants,  and 
this  apparent  influence  of  the  length  upon  the  values  led  us  to  study 
the  problem  critically.  The  heat-production  per  square  meter  of  body- 
surface  per  24  hours  was  therefore  divided  by  the  total  length  of  the 
infant — an  admittedly  somewhat  empirical  procedure — and  the  result- 
ing values  were  plotted  in  a  chart  which  is  shown  in  figure  10.  Owing 
to  the  profound  disturbances  in  heat  regulation  and  the  variation  in 
the  heat-production  values  on  the  first  day,  only  those  subjects  between 
If  and  6  days  of  age  are  included  in  this  chart.  Even  with  these 
omissions  we  have  the  results  from  48  infants  which  are  strictly  com- 
parable. 


• 

• 

•         *—  •—  - 

' 
0 

•    • 

.E 

• 

... 

•    t    t 

• 

1 

• 

•    • 

• 

1 1.0 


14.5 


11.5  »2.0  125  t  '3-0 

Cals.  per  Sq.  Meter  per  24  Hrs.  per  Cm.  of  Length 

FIG.  10. — Minimum  heat-production  of  new-born  infants  per  square  meter  per  24  hours, 
computed  per  centimeter  of  length  for  infants  between  1^  and  6  days  old.  The 
arrow  indicates  12.65  calories. 


Nearly  all  of  the  points  shown  in  this  chart  lie  between  11.9  calories 
and  13.4  calories,  there  being  but  3  points  below  11.9  calories  and  only 
5  points  above  13.4  calories.  The  40  points  which  lie  between  these 
values  show  an  average  heat-production  of  12.65  calories  per  square 
meter  of  body-surface  per  centimeter  of  length.  The  plus  or  minus 
variation  from  this  value  is,  accordingly,  about  6  per  cent  for  the  40 
infants.  It  is'  clear,  therefore,  that  in  the  5  days  following  the  first  24 
hours  of  post-natal  life,  we  have  a  close  approximation  to  constancy 
in  the  metabolism  of  these  new-born  infants,  for  while  we  may  reason- 


108  PHYSIOLOGY    OF   THE    NEW-BORN    INFANT. 

ably  question  values  varying  ±  10  per  cent,  a  uniformity  in  values  with 
variations  of  only  ±  6  per  cent,  with  but  a  few  striking  exceptions,  is  at 
least  worthy  of  serious  consideration. 

From  these  observations  we  have  derived  a  formula,  cal.  =  ZX  12.65, 
which  takes  into  consideration  both  the  length  and  the  body-surface 
and  believe  that  it  is  possible  to  compute  the  minimum  heat-production 
of  infants  per  24  hours  and  per  square  meter  of  body-surface  by  multi- 
plying the  length  I  by  the  constant  12.65,  this  constant  representing 
the  average  calories  per  square  meter  per  24  hours  per  centimeter  of 
length  as  found  from  actual  observations  made  with  this  group  of 
infants  from  If  to  6  days  old,  inclusive.  Thus  our  formula  becomes: 

Total  cal.  =  ZX12.65Xl0.3^wt2 

The  heat-production  for  the  48  infants  shown  in  figure  10  has  been 
computed  by  means  of  this  formula  and  the  results  are  compared  in 
table  14  with  the  heat-production  as  determined  by  indirect  calorimetry 
from  the  gaseous  metabolism.  The  plus  or  minus  differences  between 
the  two  values  are,  for  the  most  part,  well  inside  of  6  per  cent,  the 
widest  variations  being  in  the  case  of  infants  Nos.  53  and  54,  with 
differences  of  —11.9  per  cent  and  +12.4  per  cent,  respectively.  Aside 
from  infant  No.  75,  with  a  variation  of  — 10.6  per  cent,  practically  no 
other  values  are  found  which  vary  over  7  per  cent  from  the  value 
determined  by  indirect  calorimetry.  We  believe,  therefore,  that  we 
are  justified  in  presenting  this  formula  as  a  reasonably  accurate  means 
of  computing  the  minimum  heat-production  of  infants  from  If  to  6 
days  old. 

It  is  of  course  not  unlikely  that,  with  the  progress  of  the  interesting 
researches  of  Du  Bois  on  the  measurement  of  body-surface,  the  Lissauer 
constant  may  have  to  be  discarded.  As  the  body-surface  is  simply 
an  empirical  index  of  the  law  of  growth,  we  would  strongly  emphasize 
our  belief  in  the  advisability  of  securing  the  most  exact  measurements; 
at  the  same  time  we  would  further  express  our  disapproval  of  any  con- 
ception of  a  causal  relationship  between  body-surface  and  heat-produc- 
tion. As  an  aid  to  pediatricians,  however,  we  have  computed  various 
data  which  may  be  used  for  obtaining  the  minimum  metabolism  of 
new-born  infants.  In  table  15  the  body-surface  is  given  for  weights 
ranging  from  2  to  5  kg.,  as  computed  with  the  Lissauer  formula.  Since, 
as  brought  out  in  the  previous  discussion,  the  heat-production  per 
square  meter  of  body-surface  becomes  a  function  of  length  times  a 
constant,  we  have  also  computed  the  theoretical  heat-production  per 
square  meter  per  24  hours  for  infants  varying  in  length  from  45  to  55 
cm.,  using  the  constant  of  12.65  found  in  our  observations.  These 
values  are  given  in  table  16.  Consequently,  to  find  the  total  minimum 
heat-production  per  24  hours  for  any  infant,  which  is  of  especial  value 
to  the  pediatrician  as  indicating  a  basal  value,  one  has  but  to  multiply 


BASAL    KATABOLISM. 


109 


TABLE  14. — Comparison  of  minimum  heat-production  computed  by  different  methods. 
(Infants  l\to  6  days  old.) 


Heat  produced  per  24  hours. 

Sub- 
ject 
No. 

Length. 

Body- 
weight 
without 
clothing. 

Surface 
(Lis- 
sauer)  . 

A 

By  formula 
(length  X 

B 

By  indirect 

Difference. 

C 

D 

12.65X 
surface)  -1 

calorimetry.2 

Amount 
(A  -B). 

Per  cent 

cxioo 

B 

cm. 

kg. 

sq.  m. 

cal 

cal. 

cal. 

3 

52 

3.63 

0.243 

160 

166 

-  6 

-  3.6 

4 

46.5 

3.28 

.227 

133 

139 

-  6 

-  4.3 

6 

52 

4.32 

.273 

180 

191 

-11 

-  5.8 

8 

51 

3.48 

.236 

152 

160 

-  8 

-  5.0 

9 

51 

4.04 

.262 

169 

178 

-  9 

-  5.1 

10 

52 

3.45 

.235 

155 

162 

-  7 

-  4.3 

12 

52.5 

4.17 

.267 

177 

171 

+  6 

+  3.5 

13 

50 

3.25 

.226 

143 

138 

+  5 

+  3.6 

15 

50 

3.64 

.243 

154 

162 

-  8 

-  4.9 

16 

53 

4.03 

.261 

175 

175 

0 

0 

19 

53 

3.50 

.237 

159 

155 

+  4 

+  2.6 

20 

52 

3.54 

.239 

157 

153 

+  4 

+  2.6 

21 

50 

2.92 

.211 

134 

136 

-  2 

-  1.5 

22 

49 

2.72 

.201 

125 

128 

-  3 

-  2.3 

25 

51.5 

3.32 

.229 

149 

158 

-  9 

-  5.7 

26 

50 

3.46 

.235 

149 

151 

-  2 

-  1.3 

27 

52 

3.58 

.240 

158 

169 

-11 

-  6.5 

29 

50 

3.37 

.232 

147 

150 

-  3 

-  2.0 

30 

51 

3.33 

.230 

148 

144 

+  4 

+  2.8 

31 

53.5 

3.56 

.239 

162 

158 

+  4 

+  2.5 

32 

47.5 

3.42 

.234 

141 

140 

+  1 

+  0.7 

33 

52 

3.73 

.248 

163 

153 

+  10 

+  6.5 

34 

50.5 

2.90 

.210 

134 

134 

0 

0 

35 

54 

4.33 

.274 

187 

175 

+12 

+  6.9 

38 

51.5 

3.90 

.255 

166 

156 

+  10 

+  6.4 

40 

49.5 

2.78 

.204 

128 

134 

-  6 

-  4.5 

42 

54 

3.95 

.257 

176 

176 

0 

0 

43 

50 

3.62 

.242 

153 

165 

-12 

-  7.3 

48 

54.5 

4.52 

.282 

194 

188 

+  6 

+  3.2 

49 

47.5 

2.75 

.202 

121 

130 

Q 
t7 

-  6.9 

51 

52.5 

3.73 

.248 

165 

154 

+11 

+  7.1 

52 

50 

3.54 

.239 

151 

138 

+  13 

+  9.4 

53 

47.5 

2.87 

.209 

126 

143 

-17 

-11.9 

54 

50 

3.31 

.229 

145 

129 

+16 

+  12.4 

56 

51.5 

3.19 

.224 

146 

150 

-  4 

-  2.7 

59 

52 

3.60 

.241 

159 

150 

+  9 

+  6 

60 

52 

3.60 

.241 

159 

149 

+10 

+  6.7 

62 

49.5 

3.30 

.228 

143 

134 

+  9 

+  6.7 

63 

47.5 

2.37 

.183 

110 

109 

+  1 

+  0.9 

65 

49 

2.63 

.197 

122 

127 

—  5 

-  3.9 

67 

54 

4.74 

.291 

199 

193 

+  6 

+  3.1 

68 

46 

2.12 

.170 

99 

103 

-  4 

-  3.9 

70 

51 

3.56 

.239 

154 

153 

+  1 

+  0.7 

71 

53.5 

3.96 

.258 

175 

172 

+  3 

+  1.7 

72 

50.5 

3.29 

.228 

146 

157 

-11 

-  7.0 

74 

52 

3.63 

.243 

160 

156 

+  4 

+  2.6 

75 

47.5 

2.65 

.197 

118 

132 

-14 

-10.6 

90 

50 

3.00 

.214 

135 

138 

-  3 

-  2.2 

iSee  fig.  10,  p.  107,  and  table  16,  p.  110.         2See  table  12  p.  95. 


110 


PHYSIOLOGY   OF   THE   NEW-BORN   INFANT. 


the  values  given  in  table  16  by  the  surface  area  as  indicated  in  table  15. 
The^minimum  basal  metabolism  thus  found  will  lie  for  the  most  part 
within  a  ±6  per  cent  limit,  only  a  few  instances  being  found  outside  of 
this  and  these  rarely  varying  more  than  10  per  cent  from  the  average 
value. 


TABLE  15.  —  Body-surface  computed  from  the  Lissauer  formula  (10.3 


Body- 
weight. 

Body- 
surface. 

Body- 
weight. 

Body- 
surface. 

Body- 
weight. 

Body- 
surface. 

Body- 
weight. 

Body- 
surface. 

kg. 

sq.  m. 

kg. 

sq.  m. 

kg. 

sq.  m. 

kg. 

sq.  m. 

2.00 

0.163 

2.80 

0.205 

3.55 

0.239 

4.30 

0.272 

2.05 

.166 

2.85 

.207 

3.60 

.241 

4.35 

.274 

2.10 

.169 

2.90 

.210 

3.65 

.244 

4.40 

.277 

2.15 

.172 

2.95 

.212 

3.70 

.246 

4.45 

.279 

2.20 

.174 

3.00 

.214 

3.75 

.249 

4.50 

.281 

2.25 

.177 

3.05 

.217 

3.80 

.251 

4.55 

.283 

2.30 

.179 

3.10 

.219 

3.85 

.253 

4.60 

.285 

2.35 

.182 

3.15 

.222 

3.90 

.255 

4.65 

.287 

2.40 

.184 

3.20 

.224 

3.95 

.257 

4.70 

.289 

2.45 

.187 

3.25 

.226 

4.00 

.260 

4.75 

.291 

2.50 

.190 

3.30 

.228 

4.05 

.262 

4.80 

.293 

2.55 

.192 

3.35 

.231 

4.10 

.264 

4.85 

.295 

2.60 

.195 

3.40 

.233 

4.15 

.266 

4.90 

.297 

2.65 

.197 

3.45 

.235 

4.20 

.268 

4.95 

.299 

2.70 

.200 

3.50 

.237 

4.25 

.270 

5.00 

.301 

2.75 

.202 

TABLE  16. — Heat  values  (per  sq.  meter  per  24  hrs.)  computed  for 
varying  lengths.     (Infants  1\  to  6  days  old,  inclusive.) 


Length. 

Length  X 
constant 
(12.65)  .l 

Length. 

Length  X 
constant 
(12.65)  -1 

Length. 

Length  X 
constant 
(12.65).1 

cm. 

col. 

cm. 

cal. 

cm. 

cal. 

45.0 

569 

48.5 

614 

52.0 

658 

45.5 

576 

49.0 

620 

52.5 

664 

46.0 

582 

49.5 

626 

53.0 

670 

46.5 

588 

50.0 

633 

53.5 

677 

47.0 

595 

50.5 

639 

54.0 

683 

47.5 

601 

51.0 

645 

54.5 

689 

48.0 

607 

51.5 

651 

55.0 

696 

*See  fig.  10,  page  107. 

It  should  further  be  emphasized  that  in  the  foregoing  discussion  we 
have  been  dealing  specifically  with  the  minimum  basal  metabolism, 
and  that  this  would  not,  except  in  extremely  rare  instances,  correspond 
to  the  total  24-hour  heat-production  of  an  infant  living  in  a  private 
hospital  ward  or  the  home  nursery.  The  influence  of  feeding  and  mus- 
cular activity  would  obviously  be  superimposed  upon  these  minimum 
values,  but  we  believe  that  we  are  correct  in  saying  that  this  is  the  first 
time  we  have  information  which  may  be  considered  as  founded  upon 
sufficiently  extensive  data  to  give  us  a  true  basal  value  for  the  minimum 


BASAL   KATABOLISM.  Ill 

metabolism  of  new-born  infants.  The  problem  now  before  us  is  to 
determine  approximately  the  influence  of  the  various  superimposed 
factors  which  make  up  a  day  of  ordinary  activity. 

INFLUENCE  OF  ACTIVITY  UPON  THE  BASAL  KATABOLISM. 

As  has  already  been  pointed  out,  the  minimum  metabolism  values 
recorded  in  this  report  indicate  only  the  metabolism  when. the  infants 
studied  were  in  a  condition  of  practically  complete  muscular  repose. 
As  a  matter  of  fact,  infants  are  not  in  complete  muscular  repose  during 
the  entire  first  week  of  life,  and  there  are  periods  in  which  the  activity 
varies  from  a  general  restlessness  and  movement  of  the  limbs  to 
paroxysms  of  severe  crying.  The  probable  maximum  values  for  the 
metabolism  are  therefore  of  interest.  The  maximum  values  observed 
with  93  of  our  infants,  i.  e.,  the  values  found  in  the  periods  when  the 
maximum  respiratory  exchange  took  place,  are  given  in  table  17  and  are 
there  compared  with  the  minimum  values  previously  recorded  in  table 
12.  The  percentage  increase  found  in  the  maximum  periods  as  com- 
pared with  the  minimum  periods  is  also  given  in  table  17.  It  should  be 
borne  in  mind  that  the  values  given  in  table  17  are  not  the  highest  values 
possible  as  a  result  of  muscular  activity,  but  are  the  highest  that  were 
observed  for  the  individual  infants  in  our  study.  It  is  probable, 
however,  that  the  211  per  cent  increase  shown  by  one  of  the  infants 
represents  approximately  the  possible  maximum. 

Before  the  measurements  of  the  respiratory  exchange  were  begun 
most  of  the  infants  were  naturally  somewhat  active  as  a  result  of  bath- 
ing and  dressing  and  their  transportation  from  the  hospital  to  the  obser- 
vation room.  A  considerable  proportion  of  the  maximum  values  were 
therefore  found  in  the  preliminary  periods  of  the  observations,  but  a 
large  number  of  these  values  were  also  obtained  in  other  periods. 
With  a  few  infants  the  increase  shown  in  the  maximum  period  was 
hardly  4  per  cent,  but  the  average  for  the  93  subjects  shows  an 
increase  of  65  per  cent  in  the  maximum  heat-production  as  compared 
with  the  minimum.  In  some  instances  this  average  difference  was  very 
greatly  increased.  Thus,  values  over  100  per  cent  were  found  in  10 
instances,  the  highest  value  being  that  of  infant  No.  89,  with  which 
an  increase  of  211  per  cent  was  found  in  the  maximum  period.  On 
the  other  hand,  a  large  majority  of  the  subjects  showed  an  increase  of 
only  40  to  80  per  cent  above  the  minimum. 

Since  other  writers  have  reported  a  very  much  smaller  increment  in 
the  basal  metabolism  as  a  result  of  crying  and  muscular  activity,  a 
close  analysis  of  our  figures  is  essential.  A  possible  criticism  may  be 
raised  that  these  computations  were  based  entirely  upon  the  carbon- 
dioxide  output,  making  due  allowance  for  the  variations  in  the  respira- 
tory quotients  in  computing  the  calories  produced.  We  have  there- 
fore recomputed  the  increment  in  metabolism  for  a  considerable  number 


112  PHYSIOLOGY   OF  THE    NEW-BORN   INFANT. 

TABLE  17. — Maximum  and  minimum  heat-production  in  observations  on  new-born  infanti 


Subject 
No. 

Pulse-rate. 

Heat  produced 
(computed)  per 
24  hours. 

Subject 
No. 

Pulse-rate. 

Heat  produced 
(computed)  per 
24  hours. 

Max 
per- 
iod. 

Min 
per- 
iods.1 

Max 

Min.1 

Increase, 
maximum 
over 
minimum 

Max 
per- 
iod. 

Min 
per- 
iods.1 

Max. 

Min.1 

Increase, 
maximum 
over 
minimum 

2  

107 
135 
113 
128 
160 
162 
103 
101 
130 
135 
131 
139 
126 
110 
118 
129 
126 
139 
135 
124 
119 
139 
125 
127 
115 
140 
135 
123 
138 
117 
123 
133 
134 
135 
131 
122 
158 
119 
181 
140 
94 
120 
138 
160 
112 
126 
141 
154 

99 
97 
105 
112 
116 
117 
109 
116 
112 
113 
122 
113 
118 
105 
114 
110 
121 
114 
123 
113 
111 
112 
114 
117 
116 
129 
115 
109 
129 
119 
127 
105 
113 
119 
103 
110 
126 
107 
132 
114 
89 
96 
114 
126 
106 
124 
121 
105 

cat. 
2195 
2305 
2221 
2242 
381 
267 
2243 
2227 
2249 
352 
286 
312 
323 
2200 
205 
209 
2217 
2303 
233 
269 
2237 
326 
2195 
2218 
2193 
2225 
200 
2244 
2220 
2134 
2225 
2198 
2244 
2244 
225 
2157 
239 
2249 
2515 
2226 
2147 
2264 
209 
315 
2223 
2194 
2209 
345 

cal. 
152 
166 
139 
137 
191 
160 
178 
162 
171 
138 
162 
175 
174 
108 
155 
153 
136 
128 
158 
151 
169 
150 
144 
158 
140 
153 
134 
175 
154 
99 
156 
113 
176 
165 
136 
107 
152 
143 
188 
130 
142 
154 
138 
143 
129 
151 
150 
153 

p.ct. 
28 
84 
59 
77 
99 
67 
37 
40 
46 
155 
77 
78 
86 
85 
32 
37 
60 
137 
47 
78 
40 
117 
35 
38 
38 
47 
49 
39 
43 
35 
44 
75 
39 
48 
65 
47 
57 
74 
174 
74 
4 
71 
51 
120 
73 
28 
39 
125 

58 

120 
132 
142 
119 
146 
113 
122 
129 
136 
135 
141 
124 
125 
119 
110 
162 
118 
118 
110 
125 
127 
146 
126 
106 
138 
139 
102 
104 
145 
106 
162 
92 
115 
136 
146 
135 
142 
120 
117 
123 
124 
134 
158 
123 
135 

Ill 
112 
117 
121 
116 
125 
98 
116 
103 
122 
113 
110 
109 
106 
110 
106 
94 
100 
101 
101 
116 
109 
114 
101 
131 
109 
109 
103 
118 
96 
107 
86 
113 
112 
127 
117 
123 
99 
113 
102 
103 
130 
109 
125 
107 

cal. 
2180 
2271 
213 
2136 
2363 
2185 
2193 
2166 
2205 
2283 
185 
2222 
270 
2255 
2210 
248 
2225 
2185 
2193 
2153 
2257 
290 
2196 
131 
2332 
227 
2169 
2231 
259 
2172 
386 
2181 
2199 
2240 
2239 
2237 
2176 
2174 
2178 
160 
2228 
2295 
2251 
2215 
176 

cal. 
139 
150 
149 
123 
134 
109 
128 
127 
122 
193 
103 
142 
153 
172 
157 
164 
156 
132 
137 
109 
153 
128 
167 
95 
148 
133 
144 
120 
146 
122 
124 
138 
140 
157 
136 
136 
100 
113 
112 
98 
122 
186 
126 
130 
105 

p.ct. 
29 
81 
43 
11 
171 
70 
51 
31 
68 
47 
80 
56 
76 
48 
34 
51 
44 
40 
41 
40 
68 
127 
17 
38 
124 
71 
17 
93 
77 
41 
211 
31 
42 
53 
76 
74 
76 
54 
59 
63 
87 
59 
99 
65 
68 

3  

59  ... 

4  

60  

5 

61  
62  
63 

6 

8  
9 

64 

10  
12  

65 

66 

13  

67  

15  

68  

16  

69  

17  

70  

18  

71  

19 

72 

20  
21  
22   ... 

73  

74  
75  

25   

76  

26  

78  
79  
80  

27  

29  

30  
31  
32  
33  
34  

81  
82  
83  .  . 

84  

85  
86  
87 

35  

36  
37  

88  
89  
90 

38 

39 

42  
43  .  . 

91..  .  . 

92  

44  

93  

45  

94  

46 

95 

47 

96 

48 

97  .  . 

49  

98  

50  

99  

51 

100 

52 

101  
103  

53  
54  

EC 

104  

56  

Average  of 
93  subjects 

129 

112 

234 

143 

65 

57  

lSee  table  12,  p.  95. 

2Maximum  calculated  from  the  carbon  dioxide  produced  during  a  preliminary  period  for  which 
the  respiratory  quotient  was  not  determined. 


BASAL   KATABOLISM. 


113 


of  the  infants  who  showed  a  large  increase  in  the  heat-production 
during  the  maximum  period,  using  the  oxygen  consumption  as  a  basis 
of  calculation.  These  are  compared  in  table  18  with  the  values  pre- 
viously calculated  from  the  carbon-dioxide  production.  As  will  be 
seen  by  reference  to  this  table,  the  values  found  upon  this  basis  vary 
but  slightly  from  those  computed  from  the  carbon-dioxide  production. 
For  example,  the  large  increment  of  211  per  cent  shown  by  infant  No. 
89  in  the  maximum  period  on  the  basis  of  the  carbon-dioxide  production 
becomes  219  per  cent  when  the  calculation  is  made  on  the  basis  of  the 
oxygen  consumption,  while  with  infant  No.  13  the  increment  of  155 
per  cent  becomes  137  per  cent  on  the  basis  of  the  oxygen  consumption. 
All  of  the  other  computations  lie  distinctly  inside  these  limits. 

TABLE  18. — Periods  of  maximum  heat-production  computed 
from  the  oxygen  consumption. 


Increase  of  maximum 

Heat 

over  minimum. 

Sub- 

Dura- 

Oxygen 

produced 

ject 
No. 

tion  of 
period. 

con- 
sumed. 

(com- 
puted) per 
24  hours. 

Computed 
from 

Computed 
from 
carbon 

oxygen.1 

dioxide.2 

min. 

liters. 

cal: 

p.ct. 

p.ct. 

6 

29 

1.46 

341 

79 

99 

13 

31 

1.45 

327 

137 

155 

15 

33 

1.33 

289 

78 

77 

16 

43 

1.87 

308 

76 

78 

26 

26 

.96 

258 

71 

78 

29 

24 

1.14 

331 

121 

117 

57 

25 

1.19 

332 

117 

125 

68 

37 

1.01 

187 

82 

80 

80 

62 

2.34 

262 

105 

127 

87 

62 

2.21 

251 

72 

77 

89 

27 

1.55 

395 

219 

211 

xThe  average  respiratory  quotient  for  the  observation  was 
used  in  the  computation  as  was  done  in  computing 
the  values  in  table  17. 

2See  table  17. 

In  view  of  this  comparison,  we  may  therefore  have  every  confidence 
in  the  values  given  in  table  17,  and  fairly  conclude  that  with  the  aver- 
age infant  the  metabolism  may,  on  the  average,  be  increased  approxi- 
mately 65  per  cent  above  the  minimum  value,  with  the  possibility  of  an 
increase  of  200  per  cent,  or  even  more  when  there  is  extreme  restlessness 
and  crying. 

PULSE-RATE. 

It  has  been  clearly  demonstrated  in  previous  researches  in  this  labora- 
tory that  the  pulse-rate  is  one  of  the  best  indices  of  the  internal  mus- 
cular activity  or  degree  of  cellular  stimulus,  and  this  fact  was  taken 
into  consideration  in  selecting  the  minimum  metabolism  periods.  In 
the  earlier  investigation  the  relationship  between  the  pulse-rate  and 


114  PHYSIOLOGY  OF  THE   NEW-BORN   INFANT. 

the  metabolism  was  specifically  studied,1  but  in  the  research  on  the 
metabolism  of  new-born  infants,  the  recording  of  the  pulse-rate  was 
only  incidental  to  the  measurements  of  the  metabolism  and  a  special 
assistant  was  not  assigned  to  this  routine;  the  method  of  taking  the 
records  was  therefore  somewhat  defective.  Nevertheless,  from  6  to  8 
observations  were  made  during  each  30-minute  period  and  a  sufficient 
number  of  periods  were  used  in  averaging  to  give  reasonable  assurance 
of  the  validity  of  the  average  values  obtained.  A  study  of  the  pulse- 
records  is  therefore  desirable. 

The  observations  of  the  pulse-rate  in  the  previous  research  showed 
the  very  wide  variations  which  may  reasonably  be  expected  to  occur 
in  a  short  period.  The  infants  studied  at  that  time  included  only  a 
few  new-born  infants,  yet  the  records  obtained  in  the  later  research 
show  the  same  striking  changes  in  the  pulse-rate  that  were  found  with 
the  older  infants.  This  may  be  seen  in  table  17,2  in  which  the  average 
pulse-rates  for  the  periods  of  minimum  metabolism  are  given  and  com- 
pared with  those  for  the  periods  of  maximum  metabolism.  It  should 
be  borne  in  mind  that  these  values  do  not  represent  the  minimum  or 
maximum  pulse-records,  but  only  the  average  pulse-rates  for  those 
periods  in  which  the  minimum  or  maximum  metabolism  was  found  for 
the  individual  infants.  The  comparison  of  the  values  obtained  in 
these  periods  has  a  special  interest  in  our  study  of  the  minimum  and 
maximum  metabolism  of  new-born  infants. 

The  values  for  the  pulse-rate  during  the  periods  of  minimum  metab- 
olism ranged  from  86  for  infant  No.  90  to  132  for  infant  No.  48,  the 
average  for  the  93  subjects  being  112.  When  we  examine  the  average 
values  for  the  periods  of  maximum  metabolism,  certain  anomalous 
values  are  apparent,  but  usually  the  pulse-rate  for  the  minimum  period 
was  distinctly  lower  than  that  found  during  the  maximum  period,  the 
average  value  for  the  maximum  period  being  129,  or  17  beats  higher 
than  the  average  value  for  the  minimum  periods.  Very  great  differ- 
ences are,  however,  frequently  found  between  the  highest  and  lowest 
values.  For  instance,  with  infant  No.  6  the  pulse-rate  for  the  maximum 
period  was  160  and  for  the  minimum  period  116,  and  with  infant  No.  8 
the  averages  were  162  and  117  respectively.  With  infant  No.  73  a  still 
greater  difference  was  found,  the  values  being  162  for  the  maximum 
and  106  for  the  minimum;  essentially  the  same  values  were  found  for 
infant  No.  89,  with  whom  the  metabolism  increased  211  per  cent.  We 
may  say  with  perfect  propriety,  therefore,  that  in  general  with  new-born 
infants  the  pulse-rate  increases  with  the  metabolism,  but  we  do  not 
find  so  close  an  approximation  to  the  mathematical  relationship 
between  the  increment  in  the  pulse-rate  and  the  metabolism  as  was 
observed  with  the  fasting  man  recently  studied  in  this  laboratory.3 

Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1915,  p.  130. 

'See  page  112.  3Benedict,  Carnegie  Inat.  Wash.  Pub.  No.  203,  1915,  p.  350. 


BASAL   KATABOLISM. 


115 


TABLE  19. — Pulse-rate  of  infants  during  periods  of  approximately  minimum  heat-production 

in  first  8  days  after  birth. 


Sub- 
ject 
No. 

Sex. 

First 
day. 

Second 
day. 

Third 
day. 

Fourth 
day. 

Fifth 
day. 

Sixth 
day. 

Seventh 
day. 

Eighth 
day. 

2 
3 
4 
5 
6 
8 
9 
10 
12 
13 
15 
16 
17 
18 
19 
20 
21 
22 
25 
26 
27 
29 
30 
31 
32 
33 
34 
35 
36 
37 
38 
39 
40 
42 
43 
44 
45 
46 
47 
48 
49 
50 
51 
52 
53 
54 
55 
56 
57 
58 
59 
60 
61 
62 
63 
64 
65 
66 
67 

Female 

103 
114 

117 

120 

103 

i28 

95 

Male 

95 
101 
103 

99 
108 

13G 
144 
109 
117 

113 
125 
107 

107 

114 
127 

112 
119 

121 
129 

104 
113 

123 
115 
108 
110 
119 
115 
120 
117 
116 
107 
105 

ill 
122 
123 

Female  
Male 

112 

Male 

Male 

111 

115 

118 

ioe 

113 
113 
110 

Female 

Male                       .    . 

Female               

Female  
Male  

121 

119 
121 

121 

Female  
Female 

Male  

109 
96 
109 
120 

124 
105 

117 
118 
125 
131 
107 

111 

123 
129 
106 

138 
138 
119 

105 

124 
113 

136 
110 

123 

148 
114 

Male  

116 
110 
116 

114 
121 

Female  

Female  

Female 

Male 

Female 

Male                   .    .  . 

117 
113 
125 

121 
127 

117 
112 
137 

iis 

134 
130 
138 
115 
89 
114 
124 

116 
113 
102 

116 
111 

Female         .  .  .  .  f  .  . 

Male  
Male  
Male  
Male  
Female  
Female  
Male  
Female  
Female  
Female 

128 

129 
119 
125 
105 

130 
132 
122 

123 
119 
112 

107 

115 
111 

120 

115 
115 

114 

124 
124 
125 
124 

109 

Female 

Female  

120 

103 
99 
122 
107 

Female  
Female       

Female 

Male  

109 
105 
132 
113 

106 
122 
131 
114 

114 
136 
132 

156 

Male  

Female  

Female 

Female 

Male 

99 

93 
110 
126 
120 

108 

129 
126 
118 
125 
137 
124 

108 
115 

114 
126 
113 

111 
111 

Female 

Male 

Male 

101 
124 

106 

99 
107 
115 

122 
118 
112 
112 
126 
119 
126 

Male  
Male  

119 
119 

119 

Male  
Female  
Female  
Male  
Male 

109 
115 

121 
118 

117 

120 

Male 

114 
125 

121 
131 
125 

115 
110 
131 

Female 

Female 

98 
106 
103 

Female  ~".  
Male  

134 
115 

Male  

116 


PHYSIOLOGY    OF   THE    NEW-BORN    INFANT. 


TABLE  19. — Pulse-rate  of  infants  during  periods  of  approximately  minimum  heat-production 
in  first  8  days  after  birth — Continued. 


Sub- 
ject 
No. 

Sex. 

First 
day. 

Second 
day. 

Third 
day. 

Fourth 
day. 

Fifth 
day. 

Sixth 
day. 

Seventh 
day. 

Eighth 
day. 

68 
69 

Male  
Male  

iii 

109 

112 

115 

109 

70 

Male  

107 

100 

111 

71 

Male 

111 

100 

72 

Male  

110 

73 

Male  

106 

131 

131 

121 

74 

Male  

94 

75 

Male  

100 

113 

115 

76 

Male  

101 

78 

Male  

101 

79 

Female  

116 

124 

127 

106 

80 

Male  

109 

124 

81 

Female 

114 

82 

Male 

101 

83 

Male          .    . 

131 

122 

133 

84 

Female     

109 

115 

85 

Male       

109 

86 

Female  

103 

98 

87 

Male  

118 

113 

88 

Female 

96 

89 

Male  

107 

112 

123 

129 

90 

Male 

116 

88 

82 

91 

Female 

113 

105 

92 

Female     .  . 

112 

112 

93 

Male           

127 

94 

Male     

117 

118 

95 

Female  

123 

96 

Female  

99 

97 

Female  

113 

98 

Female 

102 

99 

Male 

103 

100 

Male 

130 

101 

Male 

109 

103 

Female  ...        ... 

125 

104 

Male  

107 

Average  

112 

114 

116 

116 

116 

122 

119 

126 

This  discussion  of  the  pulse-rate  of  new-born  infants  has  thus  far 
dealt  with  the  average  pulse-records  during  the  periods  with  either 
maximum  or  minimum  metabolism,  irrespective  of  the  age  of  the 
infant,  which  varied  from  1  to  7  days.  Since  a  study  of  the  probable 
trend  of  the  pulse-rate  of  infants  during  the  first  week  of  life  may  be 
of  particular  significance,  we  have  gathered  together  in  table  19  the 
pulse-rate  prevailing  during  the  periods  which  were  selected  for  the 
comparison  from  day  to  day  of  the  minimum  heat-production.  (See 
table  13.)  The  metabolism  in  these  periods  can  be  considered  abso- 
lutely minimum  in  but  relatively  few  instances,  but  the  values  do  repre- 
sent the  best  which  could  be  obtained  from  the  data  available  for  the 
first  8  days  of  life.  The  lowest  average  pulse-rate,  i.  e.,  112,  was  found 
on  the  first  day  of  life.  For  the  next  4  days  the  pulse-rate  remained 


PHYSIOLOGICAL   NEEDS   VS.  SUPPLY.  117 

essentially  constant,  being  114  for  the  second  day  and  116  for  the  three 
following  days.  At  the  end  of  the  week  there  was  a  distinct  increase, 
the  pulse  for  the  sixth,  seventh,  and  eighth  days  averaging  122,  119,  and 
126,  respectively. 

While  we  would  again  emphasize  the  fact  that  these  pulse-rate  obser- 
vations were  wholly  incidental  to  the  studies  of  the  metabolism,  yet 
our  previous  experience  has  led  us  to  be  so  cautious  in  our  selection  of 
average  values  and  of  minimum  values  that  we  may  say  with  confidence 
that  these  figures  represent  the  average  minimum  values  for  the  pulse- 
rate  of  a  considerable  number  of  new-born  infants  during  the  first  8 
days  of  life.  The  fact  that  the  low  pulse-rate  for  the  first  day  is  coinci- 
dental with  a  low  average  body-temperature  and  heat-production  is  only 
what  would  naturally  be  expected  in  view  of  the  results  obtained  in 
our  previous  researches  and  bears  out  the  theory  that  the  best  indices 
of  internal  muscular  activity  or  internal  cellular  activity  are  the  pulse- 
rate  and  the  body-temperature.  Under  normal  conditions  fluctua- 
tions in  the  body-temperature  are  not  so  great  as  to  define  sharply  the 
relationship  between  the  body-temperature  and  the  metabolism,  except 
when  there  is  a  febrile  temperature.  With  the  supercooling  of  these 
infants,  however,  the  low  pulse-rate  and  its  attendant  low  metabolism 
and  low  temperature  are  strikingly  in  accord. 

PHYSIOLOGICAL  NEEDS  VS.  SUPPLY. 

As  a  result  of  this  study  of  the  metabolism  of  the  new-born  infant, 
certain  fundamental  values  may  be  considered  as  definitely  established, 
namely,  the  basal  energy  requirements  of  the  new-born  infant  for  the 
5  days  following  the  first  24  hours  of  life.  Our  calculations  of  the  mini- 
mum metabolism,  upon  which  we  base  our  discussion  almost  exclusively, 
show  a  remarkable  degree  of  uniformity  in  these  values.  From  the 
tables  recording  the  minimum  and  maximum  metabolism,  data  may  be 
obtained  for  also  computing  the  approximate  energy  requirements  of  the 
new-born  child  during  a  day  of  varied  activity.  The  maximum  values 
have  been  shown  to  vary  enormously  in  individual  cases,  but  the  results 
of  the  whole  series  average  65  per  cent  above  the  basal  metabolism.1 

In  estimating  such  requirements  we  are  dealing  only  with  the  problem 
of  maintenance,  assuming  that  during  the  first  week  we  may  disregard 
the  requirements  for  actual  growth  (at  least  for  the  purposes  of  dis- 
cus^ion).  Hence  the  primal  consideration  may  be  stated  to  be:  Is  the 
normal  food-supply  of  the  new-born  infant  during  the  first  week  suffi- 
cient for  maintenance,  disregarding  any  needs  for  growth?  As  the 
evidence  that  we  have  accumulated  may  have  a  certain  directly  prac- 
tical value  in  this  connection,  the  energy  output  and  its  quantitative 
relations  to  the  energy  intake  may  very  properly  be  considered.  Prac- 
tical experience,  particularly  in  regard  to  the  noticeable  loss  in  weight 

lSee  p.  112. 


118  PHYSIOLOGY  OF  THE   NEW-BORN   INFANT. 

and  the  apparent  scant  supply  of  colostrum,  leads  us  to  expect,  a 
priori,  that  there  is  a  lack  of  balance  between  intake  and  output.  To 
attempt  any  readjustment  demands  either  (1)  a  reduction  of  the  energy 
output  or  (2)  a  more  adequate  food-supply,  or  a  combination  of  both 
factors. 

THE  CONSERVATION  OF  ENERGY. 

The  energy  output  depends  largely  upon  the  heat-regulation  of  the 
body.  The  values  previously  presented  have  indicated  that  this  heat- 
regulation  is  very  imperfect  during  the  first  day  after  birth,  since  both 
minimum  and  maximum  values  for  the  basal  metabolism  per  unit  of 
weight  or  surface  area  are  noted  on  this  day.1  Important  supple- 
mentary evidence  as  to  a  greatly  disturbed  heat-regulation  may  be 
found  in  a  study  of  the  body-temperature  of  these  infants,  for  body- 
temperature  is  the  resultant  of  thermogenesis  and  thermolysis,  and  if 
the  latter  prevails,  there  is  a  falling  temperature.  The  well-known 
factors  influencing  body-temperature  in  the  adult,  such  as  muscular 
activity  and  exposure  to  a  temperature  environment  differing  greatly 
from  that  of  the  body,  are  immediately  recognized  as  factors  entering 
into  the  early  life  of  the  new-born  infant,  thus  making  a  consideration 
of  the  fluctuations  in  the  body-temperature  imperative  in  any  adequate 
discussion  of  the  problem  of  heat-regulation  in  the  body  of  the  new- 
born infant. 

BODY-TEMPERATURE. 

The  body-temperature  of  these  infants  was  recorded  in  practically 
all  instances  just  before  and  just  after  the  observation  of  the  respira- 
tory exchange,  and  the  data  obtained  are  given  with  the  other  statistical 
data  in  table  9.2  In  many  of  the  observations  on  the  first  day  after 
birth,  the  body-temperature  rose  while  the  infant  was  inside  the  respi- 
ration chamber.  It  would  appear,  therefore,  that  the  effect  of  the 
labor,  the  bath,  and  the  exposure  incident  thereto  was  to  lower  the 
temperature  below  normal.  High  temperatures  were  rarely  noted  with 
any  of  the  infants,  but  occasionally  very  low  records  were  obtained 
when  there  had  been  undue  exposure,  such  as  in  the  bath  given  before 
the  observation  of  the  respiratory  exchange.  The  low  temperature  due 
to  this  previous  exposure  persisted  for  some  time,  but  the  temperature 
gradually  attained  the  normal  height  for  an  infant  of  this  age. 

In  order  that  a  more  definite  comparison  may  be  made  of  the  body- 
temperature  records  during  the  first  day  after  birth  with  those  obtained 
in  the  days  following,  the  average  rectal  temperature  of  our  infants  for 
each  of  the  first  8  days  is  given  in  table  20.  To  study  more  closely 
the  temperature  for  the  first  day,  we  give  also  the  records  obtained  with 
infants  studied  before  they  were  12  hours  old  and  those  studied  between 
the  twelfth  and  twenty-fourth  hours.  On  the  day  of  birth  48  infants 

^ee  figures  7,  8,  and  9,  pp.  103,  104,  and  105.  2See  pages  46  to  79. 


PHYSIOLOGICAL   NEEDS   VS.  SUPPLY. 


119 


had  an  average  rectal  temperature  during  the  first  12  hours  of  36.7°  C. 
(98.1°  F.)  and  during  the  last  12  hours  26  infants  had  an  average  tem- 
perature of  36.9°  C.  (98.4°  F.).  The  average  rectal  temperature  for 
the  infants  studied  on  the  first  day  after  birth  was  36.8°  C.  (98.2°  F.), 
on  the  second  day  37.1°  C.  (98.8°  F.),  on  the  third  day  37.2°  C.  (99.0° 
F.),  on  the  fourth  day  37.0°  C.  (98.6°  F.),  and  on  the  fifth  day  36.9°  C. 
(98.5°  F.).  While  admittedly  the  records  for  the  sixth,  seventh,  and 
eighth  days  were  obtained  with  relatively  few  infants,  the  average 
results  approximate  those  for  the  days  immediately  preceding,  being 
37.0°  C.  (98.6°  F.).  It  is  perfectly  clear  from  these  data,  therefore, 
that  the  average  rectal  temperature  of  infants  on  the  first  day  after 
birth  is  at  least  0.3°  C.  (0.6°  F.)  lower  than  on  the  second  day.  This 
observation,  taken  in  connection  with  the  fact  that  the  infants  during 
the  first  12  hours  had  a  slightly  lower  temperature  than  those  studied 
during  the  last  12  hours,  would  imply  that  the  temperature  gradually 
increased  from  the  first  to  the  third  day,  and,  indeed,  even  during  the 
first  day,  or  that  it  was  lowered  during  the  first  day  by  the  bath. 

TABLE  20. — Average  rectal  temperature  of  infants  during  first  8  days  after  birth. 


Age. 

No.  of 
subjects. 

Average  temperature. 

Age. 

No.  of 

subjects. 

Average  temperature. 

8C. 

°F. 

°C. 

°F. 

1  to  12  hrs.  . 

48 

36.7 

98.1 

4  days.  .  .  . 

51 

37.0 

98.6 

12  to  24  hrs.. 

26 

36.9 

98.4 

5  days  .... 

41 

36.9 

98.5 

1  day  

74 

36.8 

98.2 

6  days  .... 

22 

37.0 

98.6 

2  days  

65 

37.1 

98.8 

7  days  .... 

16 

36.9 

98.5 

3  days  

62 

37.2 

99.0 

8  days  .... 

9 

37.1 

98.8 

With  one  infant  the  rectal  temperature  was  recorded  at  short  inter- 
vals for  about  5  hours,  beginning  1  hour  after  birth.  Oiling  and  a 
bath  preceded  the  observations  in  the  respiration  chamber.  During 
this  preliminary  care  the  child  was  inadvertently  subjected  in  the 
hospital  to  a  longer  exposure  than  usual  and  the  temperature  of  the 
room  was  also  lower  than  had  been  customary.1  The  records  of  the 
rectal  temperature  are  given  in  table  21,  those  while  the  infant  was  in 
the  respiration  chamber  beginning  with  4h  56m  p.  m.  While  the  rectal 
temperatures  were  being  taken  in  the  chamber  there  was  necessarily 
the  same  slight  exposure  which  is  customary  when  such  temperature 
records  are  made  in  the  hospital,  but  great  care  was  taken  to  keep  the 
infant  well  wrapped  up  at  these  times. 

From  the  records  in  table  21  it  will  be  seen  that  the  rectal  tempera- 
ture rose  steadily  and  somewhat  rapidly  throughout  the  entire  period. 
It  is  not  possible,  however,  to  average  these  values  with  the  tempera- 
ture records^  obtained  with  the  other  infants,  for  in  the  majority  of 


JThe  temperature  of  the  room  was  71°  F.,  while  usually  it  is  80°  F.  or  more. 


120 


PHYSIOLOGY   OF   THE    NEW-BORN   INFANT. 


cases  the  exposure  during  the  bath  was  less  than  in  this  particular 
instance.  On  the  other  hand,  the  exposure  after  birth  was  probably 
much  less  with  our  infants  than  is  usual  in  ordinary  hospital  practice 
or  in  caring  for  the  new-born  child  in  the  home.  Accordingly  we  may 
fairly  conclude  that  when  the  infant  is  bathed  in  the  usual  way  the 
temperature  during  the  first  24  hours  is  distinctly  subnormal. 

That  the  environmental  temperature  plays  a  very  great  role  in  its 
effect  upon  the  body-temperature,  particularly  during  the  first  day  of 
life,  is  also  shown  in  certain  of  Hasselbalch's  studies,  in  which  the 
recorded  temperatures  are  frequently  extraordinarily  low.  Thus  in 
table  1  he  gives  rectal  temperatures  as  low  as  32.8°  C.  and  33.4°  C.,  while 
in  table  3  he  gives  two  temperatures  of  33.4°  C.  and  33.1°  C.1 

TABLE  21. — Rectal  temperature  of  an  infant  taken  at  frequent  intervals  during  early  hours 

after  birth. 


Time. 

Rectal  temperature. 

Time. 

Rectal  temperature. 

May  14,  1915: 
4h  06m  p.  m.1. 

°C. 
37.0 
37.0 
36.4 
35.2 
35.2 
35.4 
35.7 

°F. 

98.6 
98.6 
97.6 
95.4 
95.4 
95.8 
96.2 

May  14,  1915—  con. 
6h  44m  p.  m  
7   09    p.  m 

°C. 
36.0 
36.0 
36.3 
36.3 
36.4 
36.4 

°F. 
96.8 
96.8 
97.4 
97.4 
97.6 
97.6 

4    17    p.  m  
4   46    p.  m.  (?)  .  . 
4   56    p  m2 

7   34    p.  m 

7   59    p  m 

5   23    p.  m  

8  25    p.  m  

5  49    p.  m  
6   17    p.  m  

8   50    p.  m  

of   birth  4h  Olm  p.  m.      Bath  (oiled    first   and  then  bathed  in  water  at  102°  F.)  given 

between  4h  20™  p.  m.  and  4h  45m  p.  m.;  temperature  of  room  71°  F. 
2Placed  in  the  respiration  chamber  at  4h  56m  p.  m. 

The  observations  made  with  our  infants  indicate  that  there  is  a  dis- 
tinct correlation  between  the  body-temperature  of  the  infant  and  the 
total  metabolism,  for  on  the  days  with  low  body-temperature  the  total 
metabolism  was  likewise  low.  Indeed,  in  some  instances  when  the 
records  of  the  temperature  distinctly  indicated  a  supercooling,  the 
advisability  of  using  certain  of  the  data  has  been  questioned.  Since 
it  is  seldom  that  we  find  these  low  temperatures  other  than  on  the  first 
day  after  birth,  it  is  highly  probable  that  they  are  due  solely  to  the 
exposure  incidental  to  the  birth,  the  subsequent  bath,  and  other  special 
details  of  the  care  of  a  new-born  infant.  It  is  of  peculiar  significance, 
therefore,  that  on  the  first  day,  when  the  low  temperatures  predominate, 
we  find  likewise  a  somewhat  lower  metabolism  per  kilogram  of  body- 
weight  and  per  square  meter  of  body-surface  than  on  the  subsequent 
days,  thus  bearing  out  the  contention  that  the  metabolism  is  con- 
siderably affected  by  the  body-temperature. 

When  we  make  a  critical  analysis  of  Hasselbalch's  figures,  however, 
we  find  it  impossible  to  determine  precisely  the  influence  of  the  body- 
temperature  upon  the  metabolism,  for  we  have  no  evidence  as  to  the 


^ee  pages  20  and  22.     It  should  be  stated  here  that  Hasselbalch  calls  attention  to  the  possible 
errors  in  these  observations. 


PHYSIOLOGICAL   NEEDS  VS.  SUPPLY.  121 

exact  degree  of  the  muscular  repose  of  the  infant.  It  is  not  improbable 
that  the  chilling  effect  of  too  low  a  temperature  and  exposure  during  a 
bath  may  produce  shivering  and,  indeed,  crying,  as  the  child  attempts 
temperature  regulation  by  increased  muscular  activity.  The  low 
metabolism  induced  by  the  low  temperature  may  therefore  be  more 
than  compensated  by  an  increase  in  the  metabolism  due  to  the  efforts 
of  the  infant  to  maintain  the  temperature  by  muscular  movements. 

Since  the  metabolism  is  so  profoundly  affected  by  the  influence  of 
various  factors  upon  the  body-temperature,  it  would  appear  logical 
that  some  means  should  be  found  for  compensating  for  the  defective 
temperature  regulation  of  the  new-born  infant  —  a  deficiency  frequently 
resulting  in  a  disturbed  katabolism. 

METHODS  FOR  REDUCING  THE  ENERGY  Loss. 

Various  methods  for  preventing  an  excess  energy  output  during  the 
first  days  of  an  infant's  life  are  used  in  ordinary  practice.  Every  good 
nurse,  whether  trained  or  untrained,  knows  that  an  infant  must  be 
kept  warm  and  comfortable  and  does  everything  in  her  power  to  make 
him  so,  thus  instinctively  conserving  the  energy.  Excess  katabolism 
is,  for  the  most  part,  due  to  muscular  activity.  At  birth  the  infant 
emerges  from  warm  surroundings  in  which  the  temperature  was  37°  C. 
(98.6°  F.)  into  air  which  is  many  degrees  colder,  presumably  26.7°  C. 
(80°  F.);  the  shock  of  the  cold  air  causes  him  to  cry.  This  crying, 
however,  is  necessary  for  his  future  welfare,  as  it  expands  his  lungs  with 
air  and  prepares  them  for  their  future  work.  The  preliminary  fit  of 
crying  comes  naturally  to  most  infants  and  is  usually  induced  with 
others. 

After  this  fit  of  crying  every  legitimate  effort  should  be  made,  espe- 
cially during  the  first  days  of  life,  to  reduce  the  muscular  activity  to  a 
minimum,  and  thus  prevent  a  waste  of  energy.  The  more  time  the 
infant  spends  in  quiet  sleep,  the  less  will  be  the  katabolism.  When  a 
healthy,  new-born  baby  is  awake,  crying,  and  active,  it  is  usually 
uncomfortable  and  it  cries  from  an  instinct  of  self-preservation.  This 
discomfort  may  be  due  to  chilling,  improperly  adjusted  clothing,  wet  or 
soiled  diapers,  too  high  a  temperature  of  the  hot-water  bottles,  hunger, 
indigestion,  or  a  few  pathological  processes.1  The  infant  should  be  made 
comfortable  by  attention  to  such  minor  details  as  dry  diapers,  a  comfort- 
able bed,  protection  from  glaring  sunlight,  and  similar  precautions. 

When  too  low  a  temperature  environment  produces  chilling,  the 
infant  instinctively  attempts  to  raise  the  body-temperature  by  physical 
activity  and  thus  compensate  for  the  loss  of  heat.  For  energy  con- 
servation a  warm  environment  is  imperatively  necessary  and  all  undue 
exposure  must  be  avoided.  Since  there  must  in  consequence  be  more 


this  monograph  deals  only  with  the  normal,  healthy  infant,  it  is  not  necessary  to  speak 
further  of  the  possible  diseases  which  may  cause  an  infant  to  cry. 


122  PHYSIOLOGY   OF  THE   NEW-BORN   INFANT. 

or  less  exposure  and  a  lowering  of  the  body-temperature  in  bathing  the 
infant,  especially  in  a  room  of  ordinary  temperature,  there  is  good 
reason  for  believing  that  the  bath  should  be  omitted  on  the  first  day 
and  the  infant  should  be  simply  oiled.  This  precaution  may  be  espe- 
cially applicable  in  the  case  of  poorly-nourished,  weak,  or  premature 
infants.  The  baby  should  also  be  kept  warm  with  artificial  heat,  hot- 
water  bottles  commonly  being  used.  With  the  infants  in  our  observa- 
tions a  warm  environment  was  produced  inside  the  respiration  chamber 
by  raising  the  temperature  of  the  water-jacket  surrounding  it.  The 
fact  that  the  body-temperature  rose  in  many  of  the  observations  with 
the  respiration  chamber,  especially  on  the  first  day,  would  indicate 
that  the  conditions  were  favorable  for  conserving  the  energy  output 
during  the  first  hours  after  birth,  when  the  heat  regulation  of  the  body 
was  markedly  imperfect. 

Yet  another  reason  for  the  excess  muscular  activity  during  these 
first  days  of  an  infant's  life  may  be  the  actual  need  of  food,  for  certain 
muscular  movements  are  always  associated  with  hunger.  The  methods 
for  supplying  this  need  are,  however,  more  properly  discussed  in  con- 
nection with  the  quantitative  relations  of  the  energy  intake. 

THE  ENERGY  INTAKE. 

The  results  obtained  in  our  study  of  the  new-born  infant  show  that 
the  energy  requirements  during  the  first  week  of  life  are  by  no  means 
small.  While  these  requirements  are  not  so  large  per  kilogram  of 
body-weight  and  per  square  meter  of  body-surface  as  has  been  com- 
monly supposed,  nevertheless  there  is  a  considerable  draft  upon  body- 
material,  at  least  during  the  early  days  of  an  infant's  life,  and  it  is  not 
true  that  the  body  has  a  superabundant  supply  of  glycogen  available 
for  this  excessive  draft  upon  its  material.  As  has  already  been  noted,1 
while  there  is  a  moderate  amount  of  glycogen  present  in  the  body  of 
an  infant,  this  can  be  rapidly  depleted  and  essentially  fasting  quotients 
found  after  24  hours.  This  is  especially  the  case  if  the  infant  attempts 
by  muscular  activity  to  increase  the  body-temperature.  While  on  the 
first  day,  at  least,  the  muscular  activity  would  not  probably  be  suffi- 
cient to  compensate  for  the  low  temperature,  it  would  tend  to  deplete 
the  moderate  store  of  glycogen,  thus  producing  a  condition  approaching 
complete  inanition,  with  the  possibility  of  developing  an  acidosis.  It 
would  appear,  therefore,  that  nature  has  made  no  unusual  provision 
for  supplying  a  quickly  available  fuel  asset  in  the  form  of  body  glycogen. 

Furthermore,  the  normal  supply  of  food-material  from  the  breast 
of  the  civilized,  parturient  woman  during  the  first  few  days  of  the 
infant's  life  is  admittedly  much  less  than  is  actually  needed  for  mainte- 
nance. The  colostrum  and  the  milk  during  the  first  week  or  ten  days 
following  the  birth  of  the  child  have  been  analyzed  by  a  number  of 

JSee  pages  84  and  88. 


PHYSIOLOGICAL    NEEDS    VS.  SUPPLY. 


123 


investigators,  these  including  Pfeiffer,1  V.  and  J.  Adriance,2  Camerer 
and  Soldner,3  Czerny  and  Keller,4  and  Langstein,  Rott  and  Edelstein.5 
Bailey  and  Murlin6  also  report  the  results  of  analyses  made  by  Gep- 
hart.  The  values  reported  by  Czerny  and  Keller  are  given  in  table  22 
and  those  of  Gephart  in  table  23.  The  energy  values  per  liter  of  human 
milk  as  reported  by  Langstein,  Rott,  and  Edelstein  for  the  first  7  days 
after  birth  are  as  follows : 

First  day 1 . 500  calories  per  c.c. 

Second  day 1 . 100 

Third  day 800 

Fourth  day 750 

Fifth  day 700 

Sixth  day 675 

Seventh  day 650 

TABLE  22. — Variations  in  percentage  composition  of  woman's  milk  (Czerny  and  Keller}. 


Fat, 

Sugar. 

Protein.1 

Ash. 

Solids. 

Pfeiffer  

p.ct. 
0.758  to  9.053 
27           46 

p.ct. 
4.224  to  7.65 
5.9          7.8 

p.ct. 
1.049  to  3.04 
.9           1.3 

p.ct. 
0.104  to  0.446 

p.  ct. 
8.23  to  15.559 

V.  and  J.  Adriance     .    ... 

1.31         7.61 

5.35        7.95 

.23         2.60 

.09           .28 

9.19       15.31 

Guiraud                 

1.75        6.18 

6.7          7.7 

.85         1.4 

.10          .27 

11.2         16.3 

Camerer  and  Soldner.  .  .  . 
Schlossmann 

1.27        5.77 
1  65        9.46 

5.35        7.52 
5.2         10.90 

.824       1.87 
.56        3.4 

.11           .36 

9.41       14.11 

1Nitrogen  times  6.25. 
TABLE  23. — Results  of  analysis  of  colostrum  (Gephart). 


Day. 

Protein. 

Fat. 

Carbo- 
hydrate. 

Heat  values  per  c.c. 

Bomb 
calo- 
rimeter. 

Physio- 
logical 
heat 
value. 

Second  

p.ct. 
2.56 
2.63 
1.79 
2.06 
2.63 

p.ct. 
2.60 
3.47 
1.25 
5.45 
2.06 

p.ct. 
7.75 
5.37 
8.68 
7.04 
7.44 

cat. 
0.667 
.685 
.561 
.903 
.636 

col. 
0.626 
.643 
.532 
.870 
.594 

Third  

Average.. 

2.3 

2.9 

7.1 

.677 

.653 

The  amount  of  human  milk  secreted  by  healthy  mothers  depends 
upon  the  demands  of  the  infants,  thus  varying  with  the  weight  and 
strength  of  the  child.  That  it  also  varies  in  primiparse  and  multipart 

Pfeiffer,  Jahrb.  f.  Kinderheilk.,  1883,  20,  p.  365. 
*V.  and  J.  Adriance,  Archives  of  Pediatrics,  1897,  14,  p.  22. 
'Camerer  and  Soldner,  Zeitschr.  f.  Biol.,  1898,  36,  p.  277. 

4Czerny  and  Keller,  Des  Kindes  Ernahrung,  Ernahrungsstorungen  und  Ernahrungstherapie, 
Leipsic  and  Vienna,  1906,  p.  412-417. 

6Langstein,  Rott  and  Edelstein,  Festschrift  z.  Heubner,  Berlin,  1913,  p.  405. 
•Bailey  and  Murlin,  Am.  Journ.  of  Obstetrics,  1915,  71,  p.  526. 


124 


PHYSIOLOGY   OF   THE   NEW-BORN   INFANT. 


is  shown  by  Cramer's1  values  given  in  table  24.  It  is  obvious  that  an 
amount  of  milk  which  would  be  normal  for  one  infant  would  be  abnor- 
mal for  another,  and  for  this  reason  average  figures  as  to  the  amount 
secreted  only  give  a  general  idea  of  what  an  average  infant  might  take 
and  can  not  be  applied  to  abnormally  strong  or  weak  infants.  Von 
Reuss2  has  collected  the  estimations  made  by  a  number  of  investigators 
as  to  the  amount  of  milk  secreted  per  day  by  the  mothers  of  infants  of 
different  weights;  these  are  given  in  table  25.  The  amount  of  milk 
taken  by  the  infant  during  the  day  was  obtained  by  weighing  the  mother 
or  the  infant  before  and  after  nursing.  This  method  is  obviously 
liable  to  great  error,  especially  when  the  small  amounts  of  the  first  few 
days  are  to  be  considered. 

TABLE  24. — Amounts  of  colostrum  and  of  human  milk  secreted  per  24  hours  in  primiparoe  and 

multipart  (Cramer). 

[All  values  in  grams.] 


1st 
day. 

2d 
day. 

3d 
day. 

4th 
day. 

5th 

day. 

6th 
day. 

7th 
day. 

8th 
day. 

9th 

day. 

10th 
day. 

9  babies  of  primiparse;  av.  birth 
wt.  3,290  gm  .  .  . 

4 

78 

183 

199 

236 

299 

303 

274 

362 

384 

7  babies  of  multiparae;  av.  birth 
wt.  3,348  gm  

6 

129 

238 

324 

344 

324 

361 

365 

384 

415 

TABLE  25. — Estimation  of  the  daily  secretion  of  colostrum  and  of  human  milk  (von  Reuss). 

[All  values  in  grams.] 


Author. 

No. 
of 
cases. 

Birth-weight. 

1st 
day. 

2d 
day. 

3d 
day. 

4th 
day. 

5th 

day. 

6th 
day. 

7th 
day. 

8th 
day. 

9th 

day. 

10th 
day. 

Kruger,  1875  
Reusing,  1895  

W.  Camerer  
Denecke,  1880.  .. 
Baumm  and  Illner 
Cramer,  1901  
Feer,  1902  

10 
6 

11 
10 

5 
7 
10 
16 
3 
18 
75 
25 

3,060 
(2,220-3,650) 
3,126 

12-15 
38.3 

17 
44 
20 
2.5 

4 

17 

19 
56.7 

96 
120.8 

91 
135 
75 
10.89 
50 
22.5 
91 
13 
90 
197.8 
54 

192 
176.6 

193 
192 
80 
89.49 
177 
79.9 
190 
190 
193 
296.8 
173 

234 
220 

309 
266 
155 
192.6 
315 
175.5 
302 
370 
260 
371.5 
263 

363 

271.5 

352 

352 
218 
226 
456 
217.6 
348 
460 
339 
431 
327 

441 
296.6 

391 
365 
233 
246 
549 
242.5 
381 
440 
402 
462.8 
354 

501 
297 

467 
383 

518 
333 

621 

648 

411 

311 

552 
281.8 
450 
483 
415 
455.3 
362 

567 

562 

603 

3,528 
3,403 

Aronstamm,  1903. 
Beuthhner,  1902.. 
Klemm,  1907  
Jaschke,  1909  
Opitz,  1911  
von  Reuss 

476 

3,091 
2,700-3,416 
3,000-3,500 
2,800-4,000 

470 
485.1 
390 

467.6 

From  the  data  in  the  foregoing  tables  it  is  seen  that  even  under  the 
most  favorable  conditions  the  total  amount  of  available  energy  in  the 
colostrum  which  the  child  receives  from  the  mother's  breast  during 
the  first  few  days  is  wholly  insufficient  to  supply  the  energy  needs,  even 
when  we  consider  only  the  basal  metabolism.  Still  less  does  this  scant 

Cramer,  Klin.  Beitrag  z.  Frage  der  kunstlichen  Ernahrung  des  Neugeborenen.  Inaug.  Diss., 
Breslau,  1896.  Cited  by  Czerny  and  Keller,  Des  Kindes  Ernahrung,  Ernahrungsstorungen  und 
Ernahrungstherapie.  Leipsic  and  Vienna,  1906,  1,  p.  356. 

Von  Reuss,  Die  Krankheiten  des  Neugeborenen.     Berlin,  1914,  p.  90. 


PHYSIOLOGICAL   NEEDS  VS.  SUPPLY.  125 

fuel-supply  serve  for  the  probable  increment  above  basal  metabolism 
caused  by  the  restlessness,  crying,  and  varied  muscular  activity  of  the 
infant  throughout  the  day.  It  is  thus  seen  that  the  struggle  for 
existence  and  the  struggle  for  food  begin  simultaneously  with  the  new- 
born infant.  Since  the  food-supply  is  so  obviously  insufficient,  we 
may  ask  why  nature  does  not  provide  more  liberally  during  the  first 
few  days.  It  is  a  most  striking  fact  that  only  human  mothers  and 
new-born  infants  are  so  entirely  dependent  upon  the  care  of  others. 
The  relationship  between  this  fact  and  the  development  of  civilization 
is  most  interesting  and  leads  one  to  ask  if  this  scant  food-supply  is  a 
natural  consequence  of  civilization. 

We  may,  furthermore,  consider  whether,  in  the  absence  of  a  suffi- 
cient natural  food-supply  to  compensate  for  the  energy  outgo,  it  is 
desirable  to  supplement  the  normal  supply  of  colostrum  with  other 
food-material  until  the  milk  is  available  in  the  mother's  breast.  Pro- 
vision of  material  for  growth  may,  without  danger  to  the  child's  welfare, 
be  delayed  for  one  week  until  plenty  of  milk  is  supplied  by  the  mother. 
Since  this  would  practically  be  partial  inanition,  we  may  reason  from 
the  analogy  of  the  prolonged  fasting  experiment  recently  reported1 
that  the  infant  may  draw  upon  its  own  body-reserve  for  a  considerable 
period  of  time. 

On  the  other  hand,  a  delay  in  the  maintenance  supply  of  food  suffi- 
cient to  force  the  infant  to  subsist  upon  its  own  body-reserves  may  not 
be  without  actual  detriment.  Usually  a  healthy,  well-nourished  infant 
has  at  birth  considerable  fat,  and,  as  shown  by  our  study  of  the  respira- 
tory quotient,  a  moderate  supply  of  glycogen.  It  is  a  well-known  fact, 
however,  that  even  with  adults  during  fasting,  particularly  when  there 
is  a  deficiency  of  carbohydrate  available  for  combustion,  an  acidosis 
rapidly  develops.  This  is  strikingly  shown  with  fasting  adults  and 
with  adults  fed  on  a  carbohydrate-free  diet,2  and  has,  indeed,  been 
frequently  observed  with  young  children.3  Is  this  acidosis  dangerous, 
and  if  so,  how  can  it  be  combated?  From  our  experience  with  adults, 
apparently  the  best  method  of  combating  acidosis  is  to  feed  carbo- 
hydrate material.  If,  therefore,  supplemental  feeding  is  necessary,  it 
would  seem  on  general  principles  that  the  food-material  most  easily 
digested  and  most  readily  absorbed  for  oxidation  would  be  a  soluble 
carbohydrate.  The  carbohydrate  possessing  these  qualities  in  the 
greatest  degree  is  dextrose,  as  it  requires  no  hydrating  ferment  to 
convert  it  into  the  blood  sugar. 

If  the  infant  is  to  be  fed,  we  may  again  emphasize  the  fact  that  a 
knowledge  of  the  energy  requirement  for  the  first  week  is  most  impor- 
tant. Those  in  charge  of  the  child  at  this  time  should  therefore  have 

^Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  203,  1915. 
Benedict  and  Joslin,  Carnegie  Inst.  Wash.  Pub.  No.  176,  1912,  p.  125. 

3Schlossmann  and  Murschhauser,  Biochem.  Zeitschr.,  1913,  56,  p.  355;  see  also,  Murschhauser, 
Boston  Med.  and  Surg.  Journ.,  1914,  171,  p.  185. 


126  PHYSIOLOGY   OF   THE    NEW-BORN   INFANT. 

practical  experience  in  supplemental  feeding,  for  a  disturbance  of  the 
digestion  in  the  first  few  days  after  birth  is  most  harmful  and  may 
even  prove  fatal.  In  discussing  this  point,  Morse  and  Talbot1  say: 
"It  is  very  important,  when  beginning  to  feed  a  new-born  baby,  not 
to  give  it  too  much  food  or  too  strong  a  food.  There  is  no  time  in  a 
baby's  life  in  which  it  is  so  easy  to  disturb  the  digestion  or  at  which 
it  is  so  difficult  to  correct  the  disturbance,  if  it  is  once  caused. " 

PROBABLE  24-HOUR  ENERGY  REQUIREMENT  OF  A  NEW-BORN  INFANT  FOR 

MAINTENANCE. 

From  a  practical  standpoint,  therefore,  we  should  know  not  merely 
the  basal  metabolism  of  the  infant  during  the  first  week  of  life,  but  the 
probable  average  metabolism.  This  would  include  the  superimposed 
metabolism  due  to  varied  muscular  activity  during  the  day,  the  infant 
when  studied  in  the  respiration  chamber  being  quiet  and  with  but 
little,  if  any,  muscular  activity.  In  discussing  the  results  of  our 
research  we  have  laid  special  emphasis  upon  the  maximum  activity, 
which  we  have  found  to  vary  from  the  minimum  by  4  to  211  per  cent, 
with  an  average  variation  of  65  per  cent.2  To  form  a  conception  of 
the  true  increase  above  the  basal  metabolism,  an  estimate  of  the  general 
activity  of  the  infant  throughout  the  day  is  essential.  An  estimate  of 
the  period  of  time  in  which  the  child  has  been  asleep,  awake,  or  crying 
may  be  obtained  from  the  report  of  the  nurse,  if  the  infant  is  in  the 
hospital,  or  from  some  responsible  member  of  the  family,  if  in  the 
home.  It  is  even  possible  that  some  simple  form  of  recording  crib, 
with  graphic  attachment,3  may  be  used  to  indicate  the  degree  of  mus- 
cular activity  as  a  help  in  forming  an  estimate  of  the  amount  of  food 
necessary  for  the  total  24-hour  energy  requirement. 

Without  taking  into  consideration  the  question  of  growth  (and  in 
the  first  week  of  the  child's  life,  this  may  be  neglected)  we  may  assume 
that  for  infants  from  If  to  6  days  old  the  basal  energy  requirement  is 
44  calories  per  kilogram  of  body- weight  or  12.65  calories  per  square 
meter  of  body-surface  per  unit  of  length.  Some  10  per  cent  for  the 
portion  rejected  as  fecal  material  should  be  added  to  this  amount,  thus 
making  the  minimum  food  requirement  approximately  48  calories  per 
kilogram  of  body-weight.  The  indefinite  but  rarely  minimum  amount 
of  activity  of  the  infant  throughout  the  day  would  further  increase  the 
energy  requirement.  This  may  be  estimated  as  about  one-half  of 
the  average  maximum  metabolism  found  in  our  observations,  or  30 
per  cent,  which  would  give  an  increase  of  14  calories.  The  daily  energy 
requirement,  including  both  the  maintenance  metabolism  and  the  metab- 
olism due  to  activity,  would  therefore  be  approximately  62  calories  per 
kilogram  per  24  hours — this  estimate  making  absolutely  no  provision 
for  growth. 

^orse  and  Talbot,  The  nutrition  and  feeding  of  infants.     New  York,  1915,  p.  125. 
,    2See  table  17,  p.  112. 
"Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1915,  p.  60. 


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